PRODUCTS, ADVENTITIOUS. 



or extravasatecl from the vessels, ever act as a 

 blastema for cell- evolution ? John Hunter, as 

 is well known, hekl that extravasatecl blood 

 was capable of organization (by which term he 

 meant vascularization) ; but his statements do 

 not by any means prove that the masses, as- 

 sumed by him to be simple coagula, were not 

 in point of fact more or less extensively mixed 

 with coagulable lymph, or inflammation-exuda- 

 tion. Others have, however, endeavoured to 

 give support and greater precision to the views 

 of Hunter. Mr. Dairy m pie*, some time since 

 examining a coagulum (injected by Mr. Busk) 

 seated between the tibia and its periosteum in 

 a scorbutic patient, found its substance per- 

 meated by vessels, which he judged to be of 

 new formation. The form, mode of arrange- 

 ment, and general characters of these vessels, 

 (as we have ourselves seen,) seem to justify 

 the idea that they are really new formations ; 

 but no proof that exudation-blastema may not 

 have been present amid the extravasated blood 

 is adduced by their describer. More recently, 

 Mr. Dalrymplef, not content with ascertaining 

 the fact of vascularization of scorbutic coagula, 

 has succeeded in tracing the progress of cell- 

 development in the substance of such coagula. 

 But if vascularization existed, the humbler grade 

 of organization, signified by cell-production, 

 was to be expected ; and the new observations 

 of Mr. Dalrymple do not remove the objection 

 which in this point of view may be made to the 

 old. Still these observations show very satis- 

 factorily that the presence of blood in sub- 

 stance will not prevent the occurrence of cell- 

 evolution and of vascularization, when the 

 other conditions of its accomplishment exist. J 

 In describing H.-EMATOMATA, further on, we 

 shall have occasion to return to this question ; 

 the reader may refer also to our observations 

 on Softened Fibrin in the article on Pus. 



Secondly, the blood-elements comprised un- 

 der the title of liquor sanguinis, slightly modi- 

 fied in their relations of quantity and in their 

 vital tendencies, are capable of constituting 

 morbid blastema. By changes, such as these, 

 is educed from the blood the fluid called 

 coagulable lymph, the nature of which will 

 hereafter be more fully considered. 



Thirdly, certain elements of the blood, more 

 or less deeply modified in essential properties, 

 form the most common species of blastema. 

 And what is the nature of the modification 

 referred to ? Is it physical, chemical, or 

 simply potential ? 



(a.} As far as observation goes, the modifi- 

 cation is not of physical character. Formations 

 the most various (just as natural textures the 

 most various) spring from blastemata having 

 the same physical qualities. 



(6.) Of the chemical constitution of blaste- 

 mata at the moment of production, nothing is 

 known from actual experiment ; but that it is 

 (setting aside its saline ingredients) albumino- 

 fibrinous maybe admitted as matter of inference 

 from the source and mode of its production. 



* Med. Cliir. Trans, vol. xxiii. p. 205. 1840. 

 t Med. Chir. Trans, vol. xxvii. p. 70. 1841. 

 j See the author's vrork on Cancer, p. 51. 



101 



Scarcely, however, have these blastemata be- 

 come the seat of cell-evolution than, as is fully 

 established, their chemical composition varies 

 very materially ; while the resulting mass is in 

 some instances essentially composed of albu- 

 mino-fibrinous elements, in others it is of fatty 

 nature; in yet others it yields gelatin. The 

 question then arises whether the chemical dif- 

 ference detected in any two given morbid for- 

 mations has existed in their blastema! fluid ah 

 origine, or been effected in connection with 

 the process of cell-germination. In the ab- 

 sence of direct information on the point, it is 

 natural to apply for its elucidation to the phe- 

 nomena of healthy nutrition. Now, in the 

 evolution of the natural tissues, compounds of 

 various chemical constitutions spring into ex- 

 istence in close juxtaposition from the same 

 blastemal fluid. And this diversity of che- 

 mical combination is certainly connected in 

 some way or other with the presence of cells : 

 for one of these vesicles (while the walls of 

 all are, as far as is known, of protein-basis) 

 may be shown to have fat for its contents, 

 another pigment, another a protein-compound, 

 &c. ; whereas, previous!}' to the occurrence of 

 cell-evolution, no such chemical distinctions 

 could be established within the blastema. 

 Chemical changes and cell-evolution are then 

 connected ; but in what manner ? Conceiv- 

 ably in one or other of two ways : the 

 development of cells may be (l)a mere coin- 

 cidence with the generation of new chemical 

 compounds, or (/) it may be its cause. 

 1. That it is a mere coincidence; in other 

 words, that the cells are passive, and the blas- 

 tema itself alone active in the chemical changes, 

 cannot be admitted ; all analogy is against it. 

 Thus the importance of yeast-cells in the phe- 

 nomena of fermentation is too obvious to be 

 denied even by those, who refuse to accept 

 the view of Schwann that those phenomena 

 cannot occur at all in fermentable matters, 

 unless through the influence of cells. 2. Cell- 

 action then must have some influence as the 

 cause of the chemical changes, and may by 

 possibility be their (a) sole or (/3) their partial 

 cause. 



(a) Supposing the cells the sole agents, 

 we must admit that their solid constituents 

 (wall and nucleus) in virtue of an inherent 

 faculty (the so-called metabolic force) form 

 new compounds out of the homogeneous 

 mutter surrounding them, this matter being 

 chemically passive in the changes occurring. 

 This was Schwann's view, and he grounded 

 it on the analogy of the alleged necessity for 

 the presence of cells as a condition sine qua 

 non of fermentation in fermentable matters. 

 But, as Hcnle has urged, the influence of cells 

 is here exaggerated ; cuses are not wanting 

 in -.\hich organic matters undergo chemical 

 change through the sole agency of heat or 

 acids, independently of the evolution of cells. 

 And, it may be added, that in the progress of 

 some fermentations, yeast-cells not only do 

 not germinate, but actually disappear, as in 

 the instance of a fermenting solution of pure 

 sugar. (#) It would appear probable, then, 



H 3 



