170 



OF THE BLOOD. 



spondence between the Red and the Colorless corpuscles, either as to their pro- 

 portionate development or as to their relations to the system generally in health 

 and disease ( 174, 175). It may be surmised, then, that if the principal part 

 of the lymph-globules really go on to be developed into Red corpuscles, a part 

 may undergo a different course of evolution and become Colorless corpuscles of 

 the blood; and that, having once acquired the latter condition, they do not pass 

 beyond it, but continue to present it during their remaining term of life. Such 

 a diverse mode of evolution from germs that appear to be similar, cannot be 

 thought in itself improbable, when it is borne in mind that all the tissues have 

 their origin, directly or indirectly, in the cells of the embryonic mass, among 

 which not the slightest difference can be observed ; and that, whatever is to be 

 the ultimate destination of cells at any period of life, their early aspect is for 

 the most part extremely uniform. 



152. Composition of the Blood. The principal components of the Blood 

 having been thus separately described, we have now to inquire into the mode in 

 which they are associated in the liquid as a whole, and the proportions in which 

 they severally present themselves. These are subject, even within the limits 

 of health, to considerable variations ; some of which seem to depend upon the 

 constitution of the individual, his diet, mode of life, &c. ; whilst others are pro- 

 bably referable to the period at which the last meal was taken, and the amount 

 of bodily exertion made within a short time previous to the analysis. When 

 the results obtained by different experimenters, moreover, are brought into com- 

 parison, a very marked discrepancy is frequently found amongst them, especially 

 in regard to the relative proportions of albumen and corpuscles ; and this arises 

 in great degree from the difference of the methods of analysis employed, as has 

 been recently proved by M. Grorup-Besanez. 1 For he found that when four 

 samples of the same blood were examined by the methods adopted by four dif- 

 ferent experimenters respectively, the results were as follows. 



The first specimen was the blood of a vigorous man fifty years old : 





Becquerel 



Gorup- 



The second specimen was from a robust man twenty years old : 



Hence it is of no value whatever to bring together analyses made by different 

 methods, since no reliance can be placed on the results of their comparison ; and 

 in estimating the alterations which present themselves in morbid conditions of 

 the blood, it is of course of fundamental importance, that we should take as our 

 standard an average of analyses of healthy blood made by the same method. As 



Journ. fur prakt. Chem.," band 1. p. 346. 



