THE BLOOD AND THE LYMPH. 327 



, 0009 ,// ; and Schmidt states, that in 100 blood-corpuscles 

 95 — 98 are of equal size. With respect to the size of the 

 blood-globules in one and the same individual, it may be 

 stated in general, that it necessarily differs at different 

 times, and especially that it necessarily increases or diminishes 

 according to the varying degrees of concentration of the blood- 

 plasma; but on this subject we have scarcely any accurate 

 researches. Harting only says, that the blood-corpuscles 

 of the same individual, measured after an interval of three 

 years, presented the same mean size, whilst in the same indi- 

 vidual after a copious meal, somewhat less average dimensions 

 were exhibited (by about 000013'") and more considerable 

 extremes. It has been remarked that determinate data are 

 wholly wanting as to the number of the blood-globules, and we 

 must await the results of Vierordt's researches. But, at all 

 events, from what has been ascertained with respect to the 

 amount of solid constituents in the blood-globules, this much 

 in general may be concluded, that they are more numerous 

 in the male than in the female sex; moreover that, after 

 repeated venesection, during pregnancy and after prolonged 

 deprivation of food, they diminish in number ; and in certain 

 diseases, as chlorosis and anaemia, are also found to be much 

 more scanty than usual. At the same time, however, it is 

 certain, that all the possible variations are not as yet by any 

 means exhausted, and it can scarcely be doubted, that in every 

 individual the number of blood-cells is subject to numerous, 

 even daily changes, according to the conditions of supply and 

 waste, with which we have still to be made accurately ac- 

 quainted. The volume of the blood-cells is estimated by Harting, 

 regarding them as short cylinders, as that of a cell of 0*0763 

 cubic millimeters; and the weight, taking their specific gravity 

 as equal to that of water, and abstracting their central 

 depression, at tiratti milligramme. If, with Schmidt, the 

 blood is taken to contain 50 per cent, of corpuscles, and the 

 whole quantity of blood be estimated at 10 kilogrammes, we 

 have a total of 65 billions 570,000 millions. According to 

 Schmidt, the specific gravity of the blood-corpuscles in men, 

 is 1-0885 — 1-0889, and in women 1*0880 — 1-0886 — numbers 

 which must stand and fall with his statements respecting the 

 quantity of blood-corpuscles. Compared with the other 



