230 BLOOD. 



regenerated than in another, and on this account there will be a less 

 marked difference between the blood-cells and the plasma ; whilst, 

 on the other hand, the blood-cells may, under favourable conditions, 

 be more rapidly reproduced, and in that case also, the relation 

 between the plasma and the cells would be less unequal. Finally, it 

 may happen that the blood-cells are more rapidly destroyed in one 

 organism than in another, and hence the difficulty of determining 

 these physiologically important relations is increased. Moreover, 

 experiments of this kind have usually been instituted during the 

 manifestation of morbid processes whose various characters and 

 modes of development have not been taken into consideration. 



Since the coloured blood-cells, as we shall subsequently show, 

 are produced from colourless cells, it is not surprising that after 

 repeated or very copious venesections (Remak) the ratio of the 

 colourless cells to the coloured ones should be considerably in- 

 creased, or, at all events, that the former should be less diminished 

 in number than the latter. 



It has even been found, that during different periods of one 

 and the same blood-letting, the relation between the blood-cells 

 and the plasma is not always constant. Becquerel and Rodier, 

 who specially investigated this subject, did not arrive at any 

 definite numerical relations. lit the great majority of cases, the 

 corpuscles were diminished in the blood which flowed last, but 

 sometimes they were increased. No light, however, can be thrown 

 on this subject as long as we remain in ignorance of the physical 

 relations existing between the relative amounts of the blood and 

 of the other juices of the animal body. 



It will be long before we can hope to establish any fixed 

 relations of comparison between definite physiological processes 

 and the increase or diminution of the number of blood- corpuscles 

 in morbid blood. We constantly find the blood-cells augmented 

 in plethora, in the earlier stages of heart-disease, in spinal 

 irritation (Popp), and in cholera (C. Schmidt). It may be 

 readily conceived that a diminution in their numbers is of more 

 frequent occurrence, especially in those anaemic conditions which 

 generally supervene upon profuse diarrhoeas, prolonged suppura- 

 tions, slow intermittent fever, typhus, copious exudations, exu- 

 berant morbid growths, cerebral affections, chronic metallic 

 poisonings, and other severe diseases; in short, in all cases where 

 the formation of the blood is less than its consumption. In 

 chlorosis, which properly speaking is only an anaemic condition, 

 and which, from our ignorance of its immediate cause, has been 



