Chapter 17

Causes of weakness in animal instinct

2164. Let us summarise what has been said. — According to me, the foundation of all illness is reduced to weakness in animal instinct. It is, I think, important not to leave this discussion without adding further reflections, which more clearly summarise and list the causes debilitating this instinct by removing, or diminishing, its dominion over the material, extended element which serves as the term of the feeling which constitutes an animal.

2165. First, we recall that animal instinct is per se inexhaustible. Its limits arise solely from the way it is conditioned relative to its term, the felt element.
This element can be conceived mentally as increasing without limit in extension. There is no reason to deny that the sentient principle could extend to the whole universe if its parts were endowed with the necessary continuity. Indeed, the principle does tend to extend and to continue itself every time it adds some other part of matter to its term, the continuum. Consequently, instinct resists if a foreign body tends to divide a living body.

Second, animal instinct tends to excitation. This, too, is unlimited. Animal instinct, therefore, seconds and promotes with its activity all the movements begun in the continuum, according to the pre-established laws I have indicated.

Third, animal instinct tends to individuation, by which it rises to its greatest possible potency and obtains ever stronger and more lasting excitation. The tendency to excitation combines with forms of the elements and material molecules, and acts as follows. If, in a composite continuum of elements of immutable forms, we suppose the presence of some power seconding every motion arising in these elements, and always remaining contained within their continuity, an organisation must necessarily be formed which is more and more suitable for insuring the presence of a greater quantity and frequency of perpetual motion. In fact, this motion could be neither total nor perpetual unless it were harmonious, that is, unless the partial motions possessed unity.(134) Feeling, then, necessarily arranges itself relative to unity, its most natural and satisfying mode.

2166. If we consider animal instinct in itself, we find nothing to explain its weakness and defective state; per se, it necessarily tends to good and is capable of everything. But the explanation is certainly found in its condition, and in certain forces superior to and influencing it.

2167. The condition of the animal, that is, the corporeal term, must have three accidents: continuity, excitation, organisation. Continuity can be divided but not altogether removed because the body is essentially a continuum. Excitation can be totally removed; in this case the life instinct, which produces only the feeling of continuity, can no longer manifest any of those forces which animal functions complete. Thus, the animal ceases as a consequence of simple weakness and exhaustion. Organisation can be dissolved and with it the animal also, which has lost its individuality.(135) However, if excitation or organisation is not removed immediately by some greater force but only threatened by a foreign force, animal instinct begins the struggle I have previously described.
In addition, in the human being the sentient principle is subject to the action of the intelligent principle with which it must struggle, or at least acquire greater force or weakness.

2168. Consequently, the primal types of all malfunctions to which animality in the human being can be reduced are two:
1. simple weakness in the sentient principle;
2. an assault on the harmony of excitation.

2169. In the last case, three accidents occur:

a) Animal instinct is the weaker element in the struggle and consequently depressed; disharmony takes place in excitation and increases to the point where it dissolves unity and individuality, and leads to death.

b) Animal instinct is stronger and succeeds in overcoming or expelling the opposing force. The outcome is health.

c) Animal instinct, although stronger, produces through its violent action new disturbances in the extrasubjective element, thus creating an opponent stronger than itself, a new illness with which to struggle. At this point, one of these three accidents is renewed.

2170. Granted, therefore, that all malfunctions in animality consist in the weakness of the sentient principle and in disharmony in sensible excitation, we need to say something about both types. The proper causes of weakness in the sentient principle of the human being, which all come from two foreign principles connected with the principle (intelligence and matter), are reduced to the following.

2171. When intelligence makes us realise our impotence as we confront difficulties connected with something we ardently desire, a diminution of forces becomes evident even in the animal principle. This occurs because the intellective and sensitive principles are identified in the human being. The weakness of one is shared with the other. The lessening of awareness of one's own forces is a lessening of forces. Consequently, if intelligence notices some imminent malfunction, or one that has already taken place, passions of fear, apprehension, sadness, anxiety and so on, are manifested.(136) On the other hand, if intelligence notices an imminent good, or one which has already occurred, passions of hope, joy, and so on, are manifested. These passions, which do not remain within the sphere of intelligence, are certainly diffused within the sphere of animality. Sad passions appear when circulation and other animal functions decelerate. But the slowing down of animal passions is an obvious effect of weakness in the motor principle, that is, the sensuous instinct. This instinct shares in the affection proper to the intellective principle, and in its weakness, which consists in an enervated awareness of its own forces, in diminution of intellective feeling; awareness produces feeling and feeling produces force.

2172. Here I note that when the cause which weakens animal instinct is an intellectual passion, the weakness is not at first either disharmonious or partial, but becomes such in its successive effects because the intelligence operates immediately in the sentient principle. This principle presides, although in various ways, over the parts and functions of the animated body.

2173. The second cause reducing the activity of the sentient principle originates from the struggle present in illness. When instinct feels itself opposed by a greater force, it becomes discouraged.

2174. This occurs as a result of the union between subjective feeling and perception of the adverse extrasubjective element. When the force of the extrasubjective element is perceived together with the feeling of one's own force, the two forces are fused into a single affection by the synthetical force. At that point, the effects of unease manifest themselves. If animal instinct feels it has to struggle with a strong opponent, it decreases its action as fatigue grows until its action ceases altogether.

2175. It sometimes happens that instinct, when strong and secure and acting energetically, finds itself suddenly faced with an obstacle. It then struggles with the assistance of any force it has contracted through habit and produces some relative upset in the extrasubjective element. If the obstacles are many and lasting, the energy of instinct gradually diminishes and grows weaker. Its forces are gradually removed, as we see in chronic illness which often results from more violent diseases.

2176. The third cause debilitating the action of animal instinct is the diminution of internal stimuli. — These stimuli can diminish as a result of some preceding weakness in the instinct itself. Once the instinct has been weakened, all the movements of the machine slow down; and diminution of motion is diminution of stimulus. But internal stimuli can also be lessened by diminution of fluids, especially the blood, the principal fluid, and in general through a loss of substance. Hunger brings on sad ideas, darkens the imagination, discourages; languor sets in throughout all the limbs. These stimuli can also diminish as a result of some mechanical obstacle impeding the movement of the living machine. This happens when vessels are ossified or their free communication is impeded, or their rapidity is lessened through obstructions such as that which spreads over or blocks the air cells of the lungs. This would occur at the end of pneumonia so that the blood, unable to complete haematosis, returns to the heart almost in the state in which it had left it, that is, vein-like and inactive. The same is true if a nerve is tied, and so on.

2177. In the fourth place, the action of animal instinct is weakened as a result of the diminution of external stimuli: food, drink, fresh air, and so on. On the other hand, vital activity is increased as these factors are increased; the activity increases in various ways, according to the quality of the stimuli and the locality to which they are applied. Carbon monoxide [nitrous oxide] given to the lungs through respiration produces a special kind of hilarity; breathing in sulphur-ether induces torpor in the sensories; and so on.

2178. The fifth cause of weakness in the operation of the animal instinct is the torpor produced in the fibre by excessive stimulation.

2179. To understand this kind of torpor, we need to consider that a stimulus does not provide excitation unless it produces intestine movements in the animated molecules. If, therefore, opposing movements have been provoked so that one cancels another, as we find in excessive stimulus, the movements opposed to animal spontaneity, which now take the lower place, bring torpor to the fibre which no longer corresponds to the stimulus.

2180. Finally, if the action of instinct is for any reason concentrated and as it were used up in some part of the body or in some special function or activity, a corresponding weakness is seen in other parts, functions or activities. This, however, occurs in very different ways and in various modes, all of which have to be distinguished.

2181. Generally speaking, it is known that the part of the human body which is most used develops, grows and becomes strong. The muscles of peasants, porters and other persons employed in tiring jobs are much bigger and more powerful than those of persons leading a comfortable, delicate life. The mass of the brain seems to increase in people dedicated to study. It was said that the larger size of the cranium in ancient tribes was attributed to the weights they used to carry on their heads.

2182. One of the principal reasons why animal instinct accumulates its activity in an extraordinary way in a particular place in the body and removes it from other places is the diseasestruggle. Consequently, imbalance of force is noted in all illnesses which continually seem to have some locality, or which seem to acquire a locality as they progress. There is simultaneously excessive robustness and weakness, excessive activity in one part and inactivity in others.

2183. When external stimuli producing pleasure are applied to the animal body with a consequent increase in excitation, animal spontaneity accumulates its activity in that point in order to possess the greatest possible quantity of pleasure. The increase in nervous activity at that part also determines a great flow of fluids. If this flow is excessive, or if fluids are then lost, great harm can be done to the body. Here we have a case of the exceptional disharmony between subjective and extrasubjective phenomena, which we have indicated.

2184. If external stimuli are troublesome when applied to the body, animal instinct tries to free itself from them at that point. But this activity produces a flow of fluids or internal stimuli. As a result, it sometimes happens that the instinct endeavours contemporaneously to remove the excessive and disordered stimuli applied externally to the part, while accumulating in its place other internal stimuli. These often produce more harm in the body than the action of the external stimuli themselves which the individual is trying to expel. For example, the instinct, while endeavouring to free itself of irritation felt in the lungs, the bronchea or the trachea by coughing, accumulates so much blood in those parts that inflammation is brought about or increased. Coughing could also induce rupture in the vessels and bring the illness to an end in the worst possible way. It is especially the direction and flow of fluids which produces the comparative robustness and weakness of which I am speak- ing.

2185. The activity of the animal instinct can be concentrated in a locality and show itself in varying degrees for several reasons which I will now distinguish:

1. 1st cause: intellectual. — In ecstasy and other great intellectual actions and affections, the human being sometimes loses only consciousness of his sense-experiences; at other times, it seems that the sense-experiences themselves are truly blocked and the sensory loses its mobility. In this case, activity exhausts itself outside the body rather than in any part, although the brain, which helps the intellect by administering signs of images to fix its attention, almost always seems to retain its involvement.

2. 2nd cause: sensory. — A kind of very lively senseexperiences impedes less lively sense-experiences even though the latter belong to different sensory organs. In sleep, activity seems concentrated in the brain, in the internal faculty of feeling. Consequently, it withdraws from stimuli pertaining to exterior senses. In this case also the cause of sensory activity, which could increase in the organ of phantasy, must be sought in the confluence of fluids in that direction. When a facial or frontal branch of the fifth pair is damaged, blindness follows. This lasts for different lengths of time(137) without any lesion of the optic nerve. It seems that the brain suspends its influence on the visual nerve because of its own disturbance and because, occupied by the painful struggle, it no longer has any power to contribute to the visual operation. On the other hand, the phenomenon may have to be attributed rather to the fact that the cerebral movements caused by the wound or the blow are those which disturb the sensory movements. If so, we have to note that these movements are not altogether mechanical but animal. As such, they use some part of the activity proper to the principle of life. It is also possible that this wound, and others which induce torpor in certain sensory organs, produce this effect through some kind of alteration caused by them in the direction of the fluids bathing the organs of sensation.

2186. 3rd Cause: the concurrence of fluids. — It is precisely the concurrence of fluids (the principal internal stimuli) that we have to consider more attentively. It is an undoubted principle that 'in the locality where vital action is comparatively greater, fluids are found in greater quantity.'(138)

I say comparatively because we should always remember that the diseased state is not constituted by any absolute degree of force, but by a relative degree, that is, by the imbalance of the vital force which is excessively altered in one part compared with another which presents the symptoms of relative weakness. For example, let us grant that cold debilitates and when moderated produces a kind of re-toning, indirect effect on the fibre by removing from it an excessive stimulus which produces torpor, or by restricting it where it has been excessively dilated. If cold therefore debilitates, vital action diminishes where cold is present. This can explain why, when the skin is exposed to contact with very cold bodies, or when we move, lightly clothed, from a hot to a cold temperature, various inflammations of the mucous membranes, of the pleura, of the lungs, of the stomach and of the vesicle are caused. The vital activity is diminished relative to the blood vessels of the skin but comparatively increased relative to the internal vessels of such membranes. In this case, the fluids must flow from the exterior to the interior(139) where they become congested and stagnant, and perhaps also impel the blood from the vein-capillaries to the lymphatic vessels that are probably in immediate contact with these capillary veins.(140)

2187. Sweat, assisted through hot baths or drinks, is for the same reason suppressed through cold baths or drinks. In other words, heat renders the vessels at the internal or external surfaces more active; cold renders the same vessels comparatively less active. The direction of the fluids is changed, therefore, and it would seem that the explanation for excitation of fluid on the surface skin by hot drinks would be the law of sympathy of which I have already spoken. This law causes the sentient principle to bring similar organs into play simultaneously.

Ice is useful for slowing down obstinate haemorrhages. This effect would seem to be attributed to two causes, that is
1. physiological action by means of which the extremities of the vessels are comparatively weakened and fluid is thus forced to take a contrary direction, in other words, to recede; and
2. chemical action which by restricting the extremities of the vessels impedes the flow of fluids. Fear brings on abundant, clear, odourless flows of urine because, while lessening internal activity and increasing activity relative to the periphery, it accelerates fluids from the interior to the exterior of the body.

2188. On the other hand, irritation of the bowels suppresses secretions.(141) All the lively inflammations of an organ contained in the three splanchnic cavities suspend and alter the course of secretions. Because there is great, vital activity towards the centre, and relative weakness towards the periphery, the flow of fluids cannot be equal relative to peripheral direction. For the same reason, food provokes the flow of saliva in the mouth; a little vinegar applied to the gum or the pituitary brings on tears; an intestinal wound blocks digestion just as gastritis impedes swallowing.(142) Bichat observes that as long as food remains in the stomach the drainage of bile is limited. It increases when food passes into the duodenum. Bile is then found in quantity in the intestines and always for the same reason: as long as the stomach is stimulated by the presence of food, vital activity is great at that point and attracts fluids rather than allow them to move elsewhere.
Thus, there is no doubt that the stimulus which increases activity in the external part of the secretory or excretory conduits is one of the principal means used by nature to determine secretions and excretions.
Broussais, with other modern doctors, maintains that the great evacuations called crasis, are only the effect of the cessation of irritation of the bowels. Why does this irritation suppress natural secretions? Because it increases vital activity within and renders it comparatively weak at the periphery. Hence, the outward direction of fluids is impeded.

2189. Although natural restabilisation of the functions of the secretory organs is the effect of cessation of the cause of the illness, this does not mean that many evacuations produced artificially are not means of restoring health. Abundant sweat, provoked through drinks or steamy baths, either general or partial, dissipates obstinate encephalitis; cures for bladder trouble, purges and emetics produce the same effect through a similar cause. These are all means with which to increase the action of the sentient principle at the skin and consequently to diminish its comparative action in the internal parts. The direction of fluids is turned from inside to outside; internal stimuli which cause pain through their excess are diminished.

2190. On the other hand, we have to reflect that vital activity, when increased in one part of the human body as a result of irritation or some other cause, can be communicated to other parts either because the irritating matter changes place or because the activity itself radiates to organically continuous parts, or finally through sympathy.(143) In this case, even the part which shares in the increased activity becomes, comparatively to other parts which do not share it, more active.

2191. In addition, certain parts become less active and occasion comparatively greater activity in others. The swelling of the lymphatic glands as a result of some inflammation (for example, when the glands under the chin swell because of whitlow) appears to occur because inflammation, by rendering other parts comparatively less active, no longer allows them to draw and guide to themselves the fluids secreted by the glands. Hence, swelling and bloating of these glands. Tuberculosis, which weakens the surrounding parts or parts sympathetic with the lungs, renders other parts of the vessels further from the centre comparatively more active. The consequence is increased heat in the palms and soles of the feet, red cheeks, bright red at the root of the tongue, abundant and very liquid perspiration, diarrhoea and oedematous swellings at the extremities.(144)

2192. This comparative increase and diminution of activity, this series of effects, which in their turn become causes, immensely complicates medical science and renders variations in the zoic course very difficult to follow.

2193. If we consider fevers which begin with a cold sensation followed by considerable heat, there is apparently a flow of blood from the periphery to the centre during the cold period, and during the hot period a flow from the centre to the periphery. But because blood is brought back to the heart through the venous network and diffused at the extremities through the arterial network, it would seem necessary to infer that the venous network acquires an excessive force in comparison with the arterial network, and vice-versa. In this case the blood, when brought to the heart with greater impetus and speed, would then be sent out with equal impetus to the periphery by a reaction of the heart and the excessively stimulated arterial vessels. However, we would have to suppose that the excess of force in the venous network consists in a state of greater tension or action of the vessels. Nevertheless, the reaction of the heart and the arteries is not increased through a state of greater tension and force proper to them, but as a result of the greater stimulus by which they are excited, that is, by the greater supply and speed of blood. We need not mention crasis of the blood which necessarily appears more of an influence in continuous than in intermittent fevers.(145)

But if this hypothesis is accurate, what is the cause of the imbalance of activity between arterial and venous networks? — This is an extremely complicated question. If blood accumulates in a given locality through some comparatively increased action at that place, the accumulated, stagnant blood can and must undergo different alterations in its principles. This is shown in the case of inflammation. Such alteration can be communicated to the mass of blood and give rise to fever, the effect of such irritation or local inflammation.(146)

2194. There is no doubt that the same law of vessels which direct fluids to places where vital activity is comparatively greater depends principally on the condition of the sensory nerves.
The following observations show this:
1. When irritation is painful, it produces sympathetically greater effects.
2. When inflamed organs are endowed with a greater number of nerves, their inflammation becomes more painful and consequently causes greater alteration to animal functions.
3. Various kinds of sympathy take place more forcefully and readily in highly sensitive persons.

2195. We have to note, however, that the concentration of vital activity is ruled by contrary laws in the vascular and nervous systems. The vital activity, concentrated in the vascular system through the concourse of fluids at the point where some cause has increased it, is on the contrary propagated in the nervous system, to such an extent that its branches start from the point where it was first increased, and always act in accordance with its own laws. As a result, gastritis, for example, is accompanied by headache through nervous communication.

2196. On the other hand, inflammation which undoubtedly increases the vascular activity in the inflamed position, produces comparative weakness in other places. We see this in weight-loss, which occurs when nutrition is impeded.

2197. During digestion, when the heart and other functions are first excited, a state of weakness occurs in the organs; the external senses and muscles lose some of their activity and a tremor of cold is felt. This shows that blood no longer flows with the same abundance and impetus to the extremities. Nevertheless, the prevalent work of the stomach, which converts food into chyme, is not in this case a diseased imbalance but an undulation of physiological force. The increased activity of the stomach gradually ceases as it completes its function and distributes nourishment to the members by restoring and duly increasing their forces. This fact is entirely in conformity with the spontaneity of animal instinct.

2198. The case is similar with irritation or diseased inflammation. The only difference here is that such a state is opposed to the spontaneity of the animal instinct which now arouses bellicose activity. Parts of the body are harmed by this irritation, not nourished. Some of the harm consists in impeding nutrition of the members by withholding the flow of fluids which should be diffused in nourishing these parts. The following are some of the many facts which could be quoted. Inflammation of the kidneys often brings on atrophy in the testicular glands. Painters' colic is remarkable for the way in which the muscles between the thumb and index finger are reduced. When abscesses are present in the tunics of the tenuous intestines, the eyes go hollow and the fattiness which should support the eye diminishes considerably.

In all chronic inflammations ending in death, weight-loss is extreme and universal throughout the body; the inflamed part continues to grow until the formation of cancrena.
In a word, I believe that the principle I have noted (fluids flow to where the vital activity is comparatively increased) can alone provide the observer with a means of knowing how the intermingling vessels of the human body spread out and, as it were, constitute the body.

2199. 4th cause: excitation of the sense and motor nerves. — I said that the activity of the sentient principle is concentrated at the point where sensation is more lively. Let us consider now the concentration of activity which takes place as a result of the extrasubjective phenomena accompanying sense, that is, as a result of the movement of the nerves.
This movement is propagated in all directions from the point where the nerve has been touched. This is the result of mechanico-physiological communication, not mere communication of mechanical motion. Nevertheless, it is certain that the activity of the animal principle tires if the sensory or motor nerves are excessively stimulated. This leaves the other parts weak and, after violent movements such as convulsions, in a state of tiredness.

2200. It is equally certain that

1. Sometimes the nervous system exercises functions in which a single part is engaged. In this case, other parts remain as though they were insensitive. One example is the simultaneous presence of tensions in the spirit. Here only the brain, the organ of phantasy, plays a part while sensitivity of the skin appears to be annihilated. This also occurs in certain diseased affections where sensitivity of the skin appears to lack almost all signs of sense.

2. If the same nervous system does not exercise one of these functions, the sensitivity of the skin is sometimes increased in an extraordinary way. The reason is the same as that given relative to diseases of the brain, as we see in maniacs, hypochondriacs, melancholics and female hysterics.

2201. The fluids of the human body are internal stimulants; the nerves stimulated. As a result of their more or less prolonged action, which is also diffused sympathetically, stimulated nerves propagate activity to the vessels which they enter. Fluids flow to these points and withdraw from other parts,(147) which remain comparatively weak and give rise to greater weakness in the nerves going to them.

Notes

(134) We could recall here Aristoxenus' teaching that the animal consists in harmony.

(135) The organisation of the animal is sometimes modified slowly but profoundly as a result of the reproduction of internal stimuli which change and promote different intestine movements. All this takes place naturally according to the law of the zoic course corresponding to the type of animal. For example, what kind of operation is carried out relative to the identity of the animal in the case of the caterpillar which becomes a chrysalis, and the chrysalis which becomes a butterfly? Does the apparently new individual preserve true identity with the preceding one in such a way that the same individual is found successively under three forms? Or does one individual transform itself into another and lose its identity? Or do we have to say rather that in these transformations, there are only two individuals and that the chrysalis is either an intermediate, imperfect form, lacking individuality, or a living mixture possessed of disharmonious internal excitations which reach out for harmony and unity in order to achieve the new individuation finally found in the butterfly state? — These are questions still left untouched by natural philosophers.

(136) The soul, when it has to carry out some important animal function in the presence of one of these debilitating intellective passions, shows itself extremely sensitive, suffers disturbance and loses direction in its activity. We see this in women giving birth. If they learn of some menace to the family, or give credence to some evil old wives' tale, their strength diminishes and they withhold co-operation from childbirth. Haemorrhage and death often follow. And bad news is sufficient to interrupt the flow of milk when a woman is breast-feeding.

(137) Alexander was temporarily blinded when he was struck by a stone.

(138) This fact is certain. How is it explained? We can presume that the natural movement of the vessels, at least the capillary vessels, is peristaltic and directs the fluids to the place of greatest excitation.

(139) Why does cold, applied to the feet, determine the excretion of urine? Because comparatively it increases the action of the secretory and excretory organs of this fluid. — We need to notice that:1.it is one thing to increase the action of the entire organ, and2.another to increase the vital action of the tissue and capillary vessels of the organ. The function of the organ can be increased, without noticeable alteration to the vital activity in its tissue and capillary system, by raising the activity of the nerves which make the organ act. Only when the vital activity increases does it impede the excretion of fluids. Indeed, it retains and recalls them. Thus inflammation of the kidneys produces blockage of urine.

(140) Bichat thinks that exhaling vessels admit blood in place of serum; this would account for inflammation. — Consequently it seems that at the place of the inflammation there is a comparatively excessive activity, the cause of the accumulation of blood, and a subsequent activity, the effect of accumulated and stimulating blood. This subsequent activity attracts new blood and thus impedes the blood from dissolving in proportion to its flow there. The venous and lymphatic vessels would in this case acquire an increase of physiological activity. At the same time, they would weaken and become enlarged and thus show signs of mechanical weakness. The outcome of such congestion, especially of the lymphatic vessels, would produce new growth, the product of such a condition. The word inflammation would simultaneously embrace the overall aspect of all these phenomena.

(141) For the same reason, in the greater part of brain illnesses, such as arachnitis, hydrocephalitis, cerebral palsy, etc., the secretion of nasal mucous is impeded and the nostrils dry up. — Sometimes the re-establishment of natural secretion dissipates long-standing cerebral pain, cures convulsions, epilepsy, fits and so on. This is a sign of re-established balance between internal and external action. — On the other hand, excessive secretion often causes pain in the head, and convulsions. In this case, the internal force shows itself too weak in comparison with the external force.

(142) According to observations made by Ferrein, Tissot and Barthez, persons subject to acrimonious degeneration, after taking fatty foods which become rancid, or flatulent drinks, often experience a spasm which impedes swallowing until they have vomited what they have swallowed or released the flatulence. It is the irritating principles which provoke vital activity, while withdrawing it from some other part where symptoms of relative weakness are shown.

(143) Brousseau noted that gastric irritation precedes and accompanies skin inflammations, especially miliary fever, scarlet fever and measles. This is without doubt the same process.

(144) As I said, I understand sympathy as the law according to which the sentient principle, when it suffers or acts in one place, suffers and acts also in another place in the body, not because the second place is materially connected with the first, but solely as a result of a law governing and determining the activity of the sentient principle.

(145) There is no doubt that crasis of the blood is altered in inflammation. The blood becomes a greater stimulant as a result of the alteration of its principles. We should perhaps seek a cause of continuous fever in this rather than suppose the alteration of the principles of blood as the sole effect of fever.

(146) Note that in amputations, fever is not immediately manifest. It occurs several days later when the blood has had time to undergo alteration. When a rib has been successfully amputated, violent fever is manifested several days later. The sick person complains of acute pain in the side, pus is smelly and yellow in colour, the tongue goes black, the teeth take on a blackish patina, the sick person dies, and we find during dissection a quantity of infested serum on one side of the pleura, with whitish concretions, and so on — evident signs of alteration to the principles of the blood.

(147) It is always a question of comparative quantity of stimulus. Fluids are stimuli in various forms: 1. according to the degree of stimulation in their composition or crasis; 2. according to their quantity of flow to the part; 3. as a result of the speed or impetus with which they flow. These three ways of stimulation draw in their wake different effects, all of which need to be carefully distinguished by the wise observer of nature.