118 MANUAL OF HISTOLOGY. 



a fresh, state as they exist in the blood, namely, loaded with water. This 

 is an evil which renders all earlier analyses useless, from the fact that 

 chemists were compelled to reckon the whole amount of water contained 

 in the blood to the plasma alone, which was quite incorrect, as, instead 

 of that, it should have been distributed, of course, between the latter and 

 cells. ? The plasma, according to this mode of calculation, appeared to 

 have a naturally large proportion of water, while wide play was given to 

 the theories in regard to the constitution of moist, moving blood-cells. 



73. 



Some years ago the proportion, of moist cells in the blood was 



ascertained by Hoppe. It is necessary to have for this analysis blood 



which coagulates unusually slowly, so that the sinking cells may have 



already disappeared at the time of operation from the uppermost layer of 



the fluid. If we now ascertain the proportion of fibrin contained in a 



certain quantity of this plasma freed from cells, and likewise in a given 



quantity of blood, it is easy to find the amount of blood-plasma by a simple 



calculation, and likewise by subtraction that of the moist corpuscles. 



The following is the composition of horses' blood according to Hoppe: 



1000 parts contain 



Plasma, . 673'8 



Moist corpuscles, ...... 326*2 



1000 parts of blood-corpuscles contain 



Water, 565 



Solid constituents, . . . . . . 435 



1000 parts of plasma contain 



Water, . " 9084 



Solid constituents, . . . . . . 9T6 



Fibrin, . lO'l 



Albumen, .' 77'6 



Fats, 



Extractives, 4'0 



Soluble salts, 6 '4 



Insoluble do., . ... . 1'7 



From the foregoing analysis we see that the proportion of water in the 

 cells is not quite Jths, while in the plasma it is -j^* ns J w ith which 

 the differences in specific gravity agree (cells = 1-105 plasma = 1-027-28 

 in the human being). We shall presently find that the solid constituents of 

 the blood-corpuscle consist principally of haemoglobin, a matter which 

 is entirely absent from the plasma, whilst fibrin and albumin are sub- 

 stances belonging particularly to the latter. 



74. 



If we now turn to the consideration of the composition of the blood- 

 cells, that of the colourless elements must be passed over, in that they can- 

 not be isolated as already remarked. The little which might be said of 

 them, besides, can be more appropriately brought forward when we are 

 discussing lymph and chyle. 



Red cells, as they appear in human and all mammalian blood, are 

 structures destitute of a nucleus, consisting of a homogenous yellow gela- 

 tinous substance, in which a lively interchange of matter may be recog- 

 nised. All substances, accordingly, which are contained in the blood-cell, 

 must be so in a state of gelatinisation or solution, if we deny the presence 



