ANEMIA AND THE HPEVIFIC ANEMIAS 301 



After a severe heiuorrliag-e tlie composition of the blood changes 

 rapidly, for the fluids contained within the tissues and lymph-spaces 

 nass into the blood in large amounts. This helps to maintain blood 

 pressure, but results in. the blood containing a large proportion of 

 water and salts and a smaller amount of protein and red corpuscles ; 

 the "total alkalinity" also falls, largely because of the scarcity of 

 "fixed alkali," on account of the poverty in corpuscles and blood 

 proteins. The proportion of water increases at first more rapidly 

 than the proportion of salts, and as a consequence the size of the red 

 corpuscles is increased because of imbibition of water ; indeed, it is 

 possible that this may even be sufficient to cause hemolysis, which wall 

 happen if the isotonic streng-th of the blood becomes less than that 

 of a 0.46 per cent. NaCl solution (Limbeck), while swelling may 

 occur whenever the strength is below 0.8 per cent. The specific 

 gravity of the erythrocytes is decreased ; ^^ the depression of the freez- 

 ing point increases," while the viscosity falls. The number of plate- 

 lets is high. 



Regeneration of the blood begins veiy soon, and for some tniie the 

 number of corpuscles exceeds the proportion of hemoglobin. During 

 this time the amount of iron in the liver and spleen is decreased, it 

 being taken up to be used in the formation of new hemoglobin. If 

 the hemorrhages are numerous and the condition of anemia prolonged, 

 secondary changes in the viscera may occur, fatty metamorphosis be- 

 ing most' marked, supposedly because of decreased oxidation. Indeed, 

 many observers state that repeated bleedings greatly increase body 

 weight by causing increased fat deposition. 



Metabolic Changes. — Gies ^'^ studied the metabolism of dogs after 

 Avithdrawing a total amount of blood equal to 11.5 per cent, of the 

 body weight during four bleedings, and found that a slight and tem- 

 porary increase in nitrogenous elimination followed the bleedings, 

 owing to an increased protein katabolism. Sugar increases in the 

 blood, while albumin and laetic acid appear in the urine. After each 

 successive hemorrhage the proportion of fibrin and the coagulability 

 of the blood increase, while the proportion of the ash obtained 

 from both blood and serum remains practically unchanged (:\Ieyer 

 and Gies). Baumann ''« states that in regeneration after hemorrhage 

 the serum albumins increase more rapidly than the globulins, while 

 others have observed the opposite relation. The urine in secondary 

 anemia shows the effects of increased protein katabolism. its specific 

 gravity, total solids, and total nitrogen being raised ; the total amount 

 of urine is at first diminished because of lowered blood pressure, but 

 it soon rises above normal and later falls back to normal. The view 



soBonninger, Zeit. exp. Path.. 1012 (11), 1. 



37 Hoesslin. Hofnieister's Boitr.. 1906 (8). 431. 



38 American IMed., 1004 (8), 155 (resume of literature). 



39 Jour. Phvsiol., 1903 (29), 18. 



