PRODUCTS, ADVENTITIOUS. 



In cold alcohol and in ivater. 



107 



A peculiar substance (Phymatin)~\ 

 Chloride of sodium . . -I 

 Lactate of soda . j 



Sulphate of soda . . J 



In water but not in alcohoh 



Casein .... 

 Chloride of sodium . 

 Sulphate of soda 

 Phosphate of soda 



Neither in alcohol nor in water. 



Casein (altered by heat) . 



Oxide of iron . 



Phosphate of lime . . ' }- G5 1 1 



Carbonate of lime 



Magnesia . 



Sulphur .... 



99.91 



Phymatin ((pv^a, a tubercle ; like pyin, the 

 discovery of Gueterbock,) is described as a pe- 

 culiar extractive matter, not precipitated from 

 its solution by extract of galls, very little by 

 neutral acetate of lead and nitrate of silver, 

 but, on the contrary, very copiously by basic 

 acetate of lead ; sulphate of copper gives no 

 precipitate, according to Gueterbock ; a white 

 flocculent one, according to Preuss. The main 

 protein-constituent of tubercle appears, from 

 the above analysis, to be casein. But nume- 

 rous chemists question the correctness of this 

 analysis, precisely in respect of the casein ; and 

 it certainly appears proved that Preuss had not 

 furnished sufficient evidence of the nature of 

 the protein-compound contained in tubercle. 

 Scherer* has endeavoured to establish the re- 

 lations of this organic material to protein, and 

 dwells upon the fact that according to the lo- 

 cality of the diseased product this may be 

 theoretically formed by adding to or taking 

 from protein a varying number of atoms of 

 oxygen, hydrogen, and carbon. The formula 

 of protein, as given by different chemists, it is 

 to be remembered, varies, its very existence 

 is made matter of question ; we are, therefore, 

 unable to discover in what manner the che- 

 mistry of the formation of tubercle can be 

 considered to be advanced, or to be likely at 

 present to be advanced, by speculations of this 

 class. The insignificance of such hypotheses 

 becomes apparent, too, from the fact that some 

 of the analyses of tubercle differ as much from 

 others as these do from the analyses of cancer ! 

 M. Boudet f finds, with respect to its organic 

 constituent, that tubercle yields albumen and a 

 matter analogous to casein, under the action of 

 cold water, and is reducible to a substance 

 having the characters of fibrin ; he further dis- 

 covers that casein, insoluble in crude tubercle, 

 becomes soluble eventually through the deve- 

 lopment of alkali : a series of propositions 

 more striking than satisfactory. 



* Simon's Chemistry, vol. ii. p. 430. 1846. 

 f Bulletin de 1'Acad. Royale de Medt'cine, t. ix. 

 p. 1160. 



Tubercle is insusceptible of growth, properly 

 so called : it increases in size by accretion of 

 new particles or by gradual coalescence of mi- 

 nute masses, at first'separated from each other 

 by appreciable intervals. In the lung the latter 

 mode of enlargement is invariably observed, 

 where the tubercle is of any size ; hence the 

 constancy of septa, as already referred to. 



Tubercle.having subsisted for a variable time 

 in the firm (or, as it is called, crude) state, 

 tends to undergo either of the following 

 changes : (1.) to become invested by a cyst ; 

 (2.) to decay by a process known as softening. 

 (1.) In certain situations, more especially 

 the bronchial and mesenteric glands and bones, 

 tuberculous matter, undergoing gradual in- 

 spissation, occasionally becomes invested with 

 a cyst (of fibrinous origin), which cuts it off 

 from the surrounding textures, and renders it, 

 comparatively speaking, innocuous. 



(2.) When tuberculous matter has existed 

 for a certain but variable period in the state of 

 firmness or " crudity," it in the vast majority of 

 cases softens. In this new state its physical 

 characters are either very closely similar to 

 those of thick deep-yellow pus, or (which is 

 more common) it seems to consist of two 

 materials, the one soft, friable, and caseiform, 

 the other more or less watery and transparent, 

 mixed together in variable proportions. Com- 

 mencing "by possibility at any part of the 

 tubercle, this process commences more com- 

 monly towards the centre, or at least within 

 the area of the tubercle, than on its confines. 

 The process of softening must either be of 

 intrinsic or extrinsic origin. Laennec, looking 

 on tubercle as vascularized, presumed the 

 change to be intrinsic, and dependent? on some 

 morbid condition of vascular action ; an hypo- 

 thesis which existing knowledge refuses utterly 

 to justify. Other pathologists taught that all 

 changes in the consistence of tubercle de- 

 pended on actions going on in the surround- 

 ing textures suppurating, infiltrating, disin- 

 tegrating. The latter doctrine is doubtless 

 correct "in part; a tubercle, softened at the 

 periphery or even in its central parts, when 

 these are permeated by natural textures, has 

 in many instances simply undergone disinte- 

 gration" from saturation with fluids produced 

 by those textures. But when a large mass 

 of tubercle (as in the brain or in a lym- 

 phatic gland) liquefies in the centre, where it 

 is absolutely beyond the reach of influence 

 from the circumjacent tissues, some intrinsic 

 change has evidently occurred. And this in- 

 trinsic change seems assimilable to that effect- 

 ing softening of fibrinous clots in the veins, 

 and is in intimate nature probably chemical. 



Tubercle, once deposited, is not necessarily 

 a fixture in the locality it occupies; on the 

 contrary, its removal from the body is fre- 

 quent, and occurs under different conditions 

 and in different manners. It is effected ; (a) 

 probably by simple absorption ; (b) by absorp- 

 tion combined with so-called " transforma- 

 tion ;" (c) by elimination. 



(r?) Existing knowledge concerning the 

 simple absolution of tubercle is far from satis- 



