IN VARIOUS PHYSIOLOGICAL CONDITIONS, 255 



method we hope at once to conform to the ordinary mode of 

 treating the subject, and to satisfy the requirements of the practical 

 physician. 



In the first place, the composition of the blood varies in the dif- 

 ferent sexes. The blood of women is generally of a somewhat lighter 

 red colour than that of men ; it is specifically lighter, and evolve sa 

 less intense odour of sweat when treated with sulphuric acid (Barruel 

 and C. Schmidt) ; it also contains more water, both in the human 

 subject and in animals. The number of the blood-corpuscles is in 

 general smaller ; but there is no perceptible difference in the quantity 

 of fibrin in the blood of the two sexes ; hence the serum of coagulated 

 women's blood preponderates over the clot or the blood-cells more 

 than that of men's blood. The serum of the blood in the two 

 sexes differs less than the whole blood, although it generally 

 appears to have a somewhat lower specific gravity, and, conse- 

 quently, contains more water. As the serum preponderates in 

 women's blood, it generally contains more albumen than that of 

 men, which is richer in cruor. A similar relation exists in reference 

 to most other constituents of the serum, as, for instance, the 

 fats and extractive matters ; but this is not the case with the salts. 

 If we compare the serum of male with that of female blood, we 

 find a larger quantity of salts in the former ; if, on the other hand, 

 the collective blood of the sexes be compared, we find most 

 soluble salts in that of women. 



Pregnancy appears to exert the following action on the blood 

 of women : it is generally darker at this than at other periods ; its 

 specific gravity sinks in consequence of its becoming richer in water 

 and considerably poorer in coloured blood-corpuscles; the fibrin is 

 relatively increased, which generally causes the blood, in coagu- 

 lating, to form a very small clot with often a superficial stratum of 

 fibrin. The amount of albumen in the serum is also diminished. 

 We have no certain data regarding the fats and salts. 



The blood of children, and especially of new-born infants, is 

 distinguished by a greater abundance of solid constituents, more 

 especially of blood-corpuscles and iron, while it is poorer in fibrin. 

 It contains, however, nearly the same quantities of fat and albumen 

 as in adult life, and a much larger proportion of extractive matters, 

 and less salts. 



In advanced life, and in the female sex after the cessation of 

 menstruation, the blood becomes poorer in corpuscles ; the serum 

 also loses some of its solid constituents ; but the cholesterin 

 appears to be somewhat increased. 



