754 



NUTRITION. 



words, when the quantity of fibrin in the cir- 

 culating part is much increased, local inflam- 

 mations will be excited by very trifling causes 

 (at other times quite inoperative"), which are 

 followed by the same results as the original one. 

 But it frequently happens that the fibrinous 

 element of the blood, though increased in 

 quantity, does not possess its normal plasticity ; 

 and the deposits which are the consequence of 

 its effusion are far from being as organizable 

 as in the preceding case, and are either im- 

 perfectly organizable, or coco-plastic, or alto- 

 gether unorganizable or aplastic. The tendency 

 to such deposits may arise from various causes. 

 Thus, when the inflammation is from the first of 

 a low or asthenic character, or when the blood 

 is previously in an unhealthy condition (as, for 

 instance, when there is a deficiency in the 

 number of red particles, the presence of the 

 normal amount of which seems important to the 

 complete elaboration of the fibrin), no other 

 kind of deposit takes place from the first; and 

 even when organizable plasma has been co- 

 piously thrown out in the first instance, it is 

 not unfrequently succeeded by caco-plastic, or 

 aplastic products, either from a change in the 

 character of the inflammatory process itself, or 

 because the late products are thrown out in 

 such a position as to be cut off from that influ- 

 ence of living surfaces around, which is neces- 

 sary to their complete organization. Between 

 the organizable oreuplastic,smd the caco-plastic, 

 and ap/aatic deposits, the gradations are almost 

 insensible. The cells and fibres which are 

 characteristic of the first diminish in number 

 and are less perfectly formed; and they are 

 replaced by a granular amorphous matter, which 

 possesses but little cohesion, and which, being 

 totally incapable of entering into any form of 

 tissue, acts as a foreign body, and becomes a 

 source of irritation. The limited space allotted 

 to this subject prevents any more particular 

 description of these products from being here 

 given ; but there is one which must not be 

 overlooked, since its occurrence is very fre- 

 quent, its effects upon the system most im- 

 portant, and its character very peculiar. The 

 product alluded to is pus. This is characterized 

 by the presence of a number of cells of a pe- 

 culiar aspect, having a very tuberculated or 

 mulberry surface, which are seen floating in a 

 fluid, termed liquor puris, which is of an albu- 

 minous or low fibrinous character, being 

 entirely destitute of organizability. Now the 

 production of pus in an inflamed part, or in 

 other words, the act of suppuration, may be 

 due to one of three causes, viz., the intensity 

 of the inflammation ; the presence of air, which 

 becomes a source of irritation ; and a previously 

 vitiated state of the blood. Various attempts 

 have been made to show that the pus-globule is 

 a degenerated red or white corpuscle of the 

 blood ; but it seems more probable, however, 

 that it does not escape from the vessels as a 

 complete cell, but as a cell-germ, which may 

 have had its origin in a white corpuscle of the 

 blood ; and which, under favourable circum- 

 stances, might have produced an exudation- 

 corpuscle. At any rate, it must be regarded as 



a degenerated form of cell ; and the liquor puris 

 must be considered as analogous to the plasma 

 of the blood in a degenerated state.* 



In what manner the inflammatory process 

 determines the formation of the pus cell, and 

 the consequent degradation of the product, we 

 are at present unable to state; but that the 

 degree of irritation in the part has an influence 

 upon it is evident from the effects of the contact 

 of air upon inflamed surfaces, causing those 

 elements to take the form of pus, which would 

 otherwise have been thrown out as a plastic 

 deposit. This circumstance would seem to 

 indicate, beyond all doubt, that the exudation 

 and pus-corpuscles, the plastic lymph, and the 

 aplastic liquor puris have the same origin, but 

 that their character is determined by local cir- 

 cumstances. There is great reason to believe, 

 that when pus is introduced into the blood, it 

 may induce such a change in the character of 

 the fluid, as speedily to impair its vital proper- 

 ties ; so that the pus-corpuscles will rapidly 

 propagate themselves in the blood, and the 

 plasticity of the liquor sanguinis will be dimi- 

 nished. In this manner the whole system will 

 be seriously affected, and there will be a tend- 

 ency to deposits of pus in various organs 

 especially those which, like the lungs and liver, 

 serve as emunctories to the system without 

 any previous inflammatory changes in these 

 parts. 



The last form of disordered nutrition which 

 we shall consider is that which takes place in 

 the tuberculous diathesis, and which is marked 

 by the deposition of tubercular matter, in place 

 of the normal elements of tissue, both in the 

 ordinary process of nutrition, and still more 

 when inflammation is set up. From an exami- 

 nation of the blood of tuberculous subjects it 

 appears that the fibrinous element is not defi- 

 cient in amount, but that it is not duly elaborated, 

 so that the coagulum is loose, and the red cor- 

 puscles are found to bear an abnormally iow 

 proportion to it. We can understand, therefore, 

 that such a constant deficiency in plasticity 

 must affect the ordinary nutritive process; and 

 that there will be a liability to the deposit of 

 caco-plastic products, without inflammation, 

 instead of the normal elements of tissue. Such 

 appears to be the history of the formation of 

 tubercles in the lungs and other organs, when 

 it occurs as a kind of metamorphosis of the 

 ordinary nutritive process; and in this manner 

 it may proceed insidiously for a long period, so 

 that a large part of the tissue of the lungs shall 

 be replaced by an amorphous deposit, without 

 any other ostensible sign than an increasing 



* It would not seem improbable that the liquor 

 puris is the product of the action of the pus-cor- 

 puscle, in the same manner as we have endeavoured 

 to show that the liquor sanguinis is the result of the 

 elaborating action of the colourless corpuscles of the 

 blood. This idea seems confirmed by the obser- 

 vation of Mr. Gulliver, that thepyogenic membrane 

 which lines the cavity of an abscess, and from 

 which the fluid appears to be secreted, is chiefly 

 composed of cells that bear a strong resemblance, on 

 the one hand to the pus-corpuscles, and on the 

 other to the colourless corpuscles of the blood ; 

 these cells are held together by fibrinous fibrils. 



