ITS ORIGIN. 305 



translations of the capillaries, the view which is based on the 

 difference in the capillaries will derive additional support from the 

 chemical investigation of the transudations of the different capillary 

 systems. Thus, for instance, C. Schmidt* has drawn the follow- 

 ing conclusion from the comparison between the composition of the 

 transudation of the capillaries of the peripheral membranes of the 

 brain, and that of the transudation which issues from the central 

 capillaries of the same organ ; namely, that the fluid of the brain 

 and spinal cord is by no means mere blood-plasma separated, as it 

 were, by mechanical filtration from the more widely circulating 

 blood-cells, and robbed of some portion of the nitrogenous and fatty 

 matters, which are taken up by the cerebral substance. When we 

 proceed to consider the exudations, we shall have to revert to 

 those investigations of Schmidt which tend to show that the fluids 

 permeating through the different capillary systems of the body 

 possess a constitution, which, although constant for the same 

 system, differs in the different systems, exhibiting its principal 

 differences in respect to the amount of albumen, while the 

 inorganic constituents remain nearly the same as in the blood. 

 According to Schmidt's investigations, protein-bodies transude 

 through the capillaries of the pleura in the largest quantity; 

 scarcely half so large a quantity passing through the capillary 

 vessels of the peritoneum, still less through those of the brain, and 

 least of all through those of the subcutaneous areolar tissue. 



These, and similar points of consideration, appear to us to be 

 necessary for the establishment of a physiologico-chemical investi- 

 gation of the origin and physiological import of the lymph ; for 

 any chemical equation would afford a false representation of the 

 sources of the lymph, and of its importance in respect to animal life, 

 if it were derived from the simple chemical analysis of the lymph 

 of the larger vessels, without reference to these points. Unfortu- 

 nately, however, we are here merely on the borders of a department 

 in which we scarcely know the course or the direction which may 

 lead us to the object of our inquiries. Nasse was the first who 

 endeavoured to throw light on this subject, by comparing, as we 

 have already mentioned, the serum of the blood of the horse with 

 the lymph taken from the cervical region of the same animal. The 

 following are the results of this inquiry. 



The lymph always contains more water than the liquor san- 

 guinis ; hence it is not perfect plasma which is exuded from the 

 blood ; but proportionally more water and less solid constituents 



* Charakteristik der Cholera, u. s. w. S. 124148. 

 VOL. II. X 



