228 BLOOD. 



pregnancy, before the period of menstruation, and after its entire 

 cessation towards the close of the climacteric period. 



We are especially indebted for the determination of these 

 relations to Becquerel and Rodier, who give 127'2 as the mean 

 number for the corpuscles of the blood of women. Nasse, in his 

 experiments on the blood of animals, has found the same differences 

 in the different sexes. 



Prevost and Dumas*, Bertholdf and SimonJ have shown by 

 direct investigations, as might indeed be conjectured, that the num- 

 ber of blood-corpuscles varies in the blood of different animals ; and 

 more recently the same subject has been fully considered, especially 

 by Nasse, but likewise by Andral, Gavarret, and Delafond.|| 

 According to these researches, it would appear that the cold- 

 blooded animals contain far fewer blood-cells than those having 

 warm-blood, birds on an average more than mammalia, but carni- 

 vorous not more than herbivorous animals. The blood of the pig 

 contained relatively the largest number of cells. 



Nasse found in the blood of the pig 145*5 p.m. of dry blood- 

 corpuscles, in that of the hen 144*6, of the goose 121*4, of the 

 dog 123-8, of the ox 121*8, of the horse 117*1, of the cat 113*4, 

 of the calf 102'5, of the sheep 92*4, and in that of the goat 

 only 86'0 p.m. The results obtained by the other enquirers 

 can only be compared with one another, but do not admit of a 

 comparison with those of others. It is worthy of notice that 

 Prevost and Dumas found the corpuscles in the blood of the land- 

 tortoise to be very abundant, and even relatively more numerous 

 than in the blood of the duck, the raven, and some of the 

 mammalia. The correctness of these numbers ought to be inves- 

 tigated, since land-tortoises bear great affinity in an anatomical 

 point of view to birds, whilst sea-tortoises stand in a nearer 

 relation to fishes. 



It may be shown with tolerable accuracy, that the quantity of 

 the corpuscles is not the same in the blood of all the vessels ; for 

 when, for instance, the urinary secretion is very active, the venous 

 blood in the kidneys will contain relatively more corpuscles than 

 the arterial blood of those organs. In consequence of the essential 



* Bibliotheque nouvelle, T. 4, p. 125. 



f Beitrage zur Zootomie, u. s. w. Gottingen, 1831. 



* Lehrb. d. Ch. Bd. 2, S. 235 [or vol. i., p. 339 of the English translation]. 

 Handworterbuch der Physiologie. Bd. 1, S. 138 ; and Journ. f. prakt. 



Ch. Bd. 28, S. 146. 



|| Ann. de Chim. et de Ph. 3me Sr. T._5, p. 304. 



