CONSTITUENTS OF THE BLOOD-CORPUSCLES. 187 



venous blood ; thus in the corpuscles of the arterial blood of a 

 horse I found only about half as much fat as in those of its venous 

 blood; in the latter the amount being 3'595-g-, and in the former, 

 1'824 of the dry prepared corpuscles. 



The so-called extractive matters of the blood cannot be accurately 

 indicated, since they are substances of which we have no knowledge ; 

 but this much is established from the few investigations which I 

 have made on this subject, namely, that most of such substances 

 pertain to the serum and not to the blood-cells. While 100 parts 

 of the solid residue of the serum contain about 8 parts of extractive 

 matters free from saline constituents, 100 parts of the solid residue 

 of the cells of the same blood (calculated from the analysis of the 

 clot) do not contain 6 parts of such substances. 



In regard to the mineral constituents of the blood- corpuscles, 

 very different views have been held regarding them, which are all 

 almost equally removed from the truth ; this observation, however, 

 does not extend to the iron. It has either been believed that all the 

 salts which we find, or presume to exist, in the serum, must also be 

 contained in the blood-cells, or it has been assumed that at all 

 events the soluble salts, especially the chlorides of sodium and 

 potassium, are altogether excluded from the cells. Although neither 

 of these views is yet generally adopted, and in the absence of all 

 means of deciding between them, we refrain from a definite opinion, 

 yet at all events the ideas at which we arrive from analysing the 

 blood point only to these two modes of considering the subject. 

 We are indebted to the unremitting investigations of C. Schmidt 

 for a series of facts which prove that, in reality, soluble salts are also 

 contained in the moist blood-cells, that these salts are by no 

 means perfectly identical with those which we find in the serum, 

 and finally, that their quantity is far smaller than it must be if the 

 water of the blood-corpuscles contained exactly the same amount 

 of saline matter as the water of the serum. 



We need only institute a comparison between good analyses of 

 the serum and of the clot of the same blood, and by a most simple 

 calculation, subtract the soluble salts occurring in the serum 

 (surrounding the cells) from the sum of the soluble salts of the 

 clot, to convince ourselves that by far less of such salts can be 

 contained in the blood-cells than in the serum, but at the same 

 time that these salts cannot pertain to the enclosed serum alone. 



Thus, for instance, in the serum of the venous blood of a horse 

 I found 0*835 of salts (soluble and insoluble), and in the moist 

 clot of the same blood 0*8 19^ of salts (including peroxide of iron) ; 



