COMPOSITION OF THE BLOOD-CELLS. 233 



that when the quantity of the water is decreased in the serum, it is 

 likewise similarly decreased in the blood-cells ; and in the same 

 manner, when an augmentation occurs in the former, it is also per- 

 ceived in the latter. From the observations hitherto instituted in 

 reference to morbid blood, it has been believed that we might 

 establish the following general proposition : that the quantity of 

 water contained in the blood bears an inverse relation to the number 

 of the blood-corpuscles ; but the above remarks must have suffi- 

 ciently shown that this cannot be received without a certain limita- 

 tion, more especially as the rule presents numerous exceptions. 

 The decrease in solid constituents is not limited in these cases to 

 the solid substances of the blood-cells, but extends in a corre- 

 sponding proportion to those of the serum. It is evident that 

 where there is an absolute diminution of the blood-cells and an 

 increase of the serum, the blood must, on the whole, be richer 

 in water when the heavier morphological elements are diminished. 

 When we treat of the serum, we will enter more fully into the 

 relations on which the greater or lesser quantity of water in the 

 blood depends. 



The composition of the blood-corpuscles differs, moreover, in 

 respect to their proximate solid constituents. We have seen that 

 globulin and h&matin do riot stand in a definite numerical relation 

 to each other in the coloured blood-cells. The hsematin of different 

 animals appears, from Mulder's researches, to be perfectly identical; 

 and we might, therefore, draw a conclusion from the iron con- 

 tained in the blood-corpuscles regarding the quantity of hoematin. 

 From Schmidt's calculations, which have been partly based upon 

 direct investigations, and partly on the analyses of others, it would 

 appear that, for every 1 part of metallic iron, there occur in the 

 blood of men 230 parts of corpuscles (according to Becquerel and 

 Rodier, 251) ; in the blood of women, 229 ; in that of oxen, 196'5 ; 

 in that of pigs, 223 ; and in that of hens, 307- In the first 

 stage of typhus, where the number of blood-corpuscles is 

 increased, Schmidt found the proportion as 1 : 220, and hence the 

 quantity of the hsematin was diminished. In those conditions, 

 however, in which the number of the blood-corpuscles is 

 diminished, the hsematin is relatively increased ; for he found that 

 on an average the relation between the iron and the dry blood- 

 cells was, in pneumonia, as 1 : 248 ; in chlorosis, as 1 : 269 ; and 

 in pregnancy, as 1 : 249. In the same manner, Schmidt made the 

 important observation already referred to, that the blood-corpuscles 



