256 OF THE BLOOD: 



the blood almost disappears, when the blood of males and of females of the 

 latter temperament is compared. 



190. A considerable influence is exercised on the entire amount, and on 

 the relative proportions, of the constituents of the Blood, by the previous 

 ingestiou of Food or Drink, and by the Diet habitually employed. When 

 a full meal containing oily matter is taken after a long fast, and a small 

 quantity of blood is drawn previously to the meal and at intervals subse- 

 quently, the serum, though quite limpid in the blood first drawn, shows an 

 incipient turbidity about half an hour afterwards; this turbidity increases 

 for about six hours subsequently, after which it usually begins to disappear. 

 The period at which the discoloration is the greatest, however, and the length 

 of time during which it continues, vary according to the kind and quantity 

 of the food, and the state of the digestive functions. When such milky 

 serum is examined with the microscope, the opacity is found to be due to 

 the presence of an immense number of exceedingly minute granules, identi- 

 cal with those which form the " molecular base" of the chyle ( 153). They 

 seem to be composed of two chemically distinct substances ; for when the 

 milky serum is agitated with ether, a part is dissolved, whilst auother por- 

 tion remains suspended ; and this latter is soluble in caustic potass. The 

 former, therefore, appears to be identical with the " molecular base" of the 

 Chyle, and to be of an oily or fatty nature ; whilst the latter belongs to the 

 protein-compounds, and probably constitutes the haptogeu membrane of 

 Ascherson, by which all fatty particles floating in an albuminous fluid, im- 

 mediately become invested. The Crassamentum of such blood often exhibits 

 a pellucid fibriuous ciust, sometimes interspersed with white dots; and this 

 seems to consist of an imperfectly assimilated protein-compound, analogous 

 to that found in the serum. The quantity of this varies according to the 

 amount of the protein-compounds present in the food. The increase of sac- 

 charine matter in the blood (in which it forms part of the "extractive"), 

 after the ingestion of a large quantity of saccharine or farinaceous aliment, 

 has been noticed by many experimenters. Its proportion differs much in 

 different parts of the body. It might be fairly presumed that a temporary 

 augmentation must take place in the aqueous constituent of the blood, when- 

 ever any considerable quantity of liquid is ingested ; and yet this augmen- 

 tation is much less considerable, under ordinary circumstances, than we 

 should at first be inclined to suppose. For there exist various provisions iu 

 the system (the peculiar Malpighian apparatus of the Kidneys being the 

 chief ) for rapidly freeing the blood from any superfluity of water ; and thus 

 any excess of fluid absorbed is speedily drawn off again. But further, it is 

 certain that when the vessels are already filled, absorption does not take 

 place with nearly the same readiness as after long abstinence from liquids 

 ($ 136) ; the rate of absorption being in great degree governed by that at 

 which the liquid is disposed of. The influence of the Regimen upon the 

 composition of the blood, however, appears to be more definite and constant. 

 An animal diet tends to increase the whole amount of solid matter, but 

 especially to augment the proportion of corpuscles. On the other hand, a 

 vegetable diet tends to lower the whole amount of solid matter, occasioning 

 a marked reduction in the corpuscles, whilst it seems rather to increase the 

 albumen ; thus showing that the decrease in the corpuscles is not due to a 

 deficiency in the azotized pabulum, but depends on some other condition. 

 The development of fibrin appears to take place at least as readily on the 

 vegetable, as on the animal regimen. Hence we see what may, and what 

 may not, be effected in the treatment of disease, by the adoption of a par- 

 ticular dietetic system ; for we may promote or retard the development of 



