68 ANATOMY 



Serum constitution. Toyama ('19) has examined the serum 

 for the relative abundance of the proteins at different ages. 

 His results are brought together in table 29 and chart 6. 



The change in total proteins follows the change in the re- 

 fractive index of the serum, but after puberty the percentage 

 of albumin falls, while that of globulin rises. The percentage 

 of the non-protein bodies remains constant. 



Corresponding results, though differing somewhat in detail, 

 have been reported by Robertson ('20, p. 340). 



Anti-pig natural hemolysin is found in the serum of rats of 

 both sexes usually after 30-50 days of age. It appears more 

 often in the female and especially during pregnancy and the 

 first week after parturition. In males the number of cases tends 

 to increase with lung infection (Suzuki, '20). 



Blood elements. Hemoglobin. Reichert and Brown ('09) have 

 determined that the hemoglobin crystals from the blood of the 

 Norway rat are similar to those from the Albino, but the crys- 

 tals from the blood of the house rat (M. rattus) are different. 



Weight of hemoglobin. For the weight of hemoglobin in the 

 entire animal, Abderhalden ('02) has reported the values given 

 in table 30. The observations were made in September 1901 — 

 one series for the base station at Basel and the other for the 

 elevated station at St. Moritz. 



Number. In the adult albino rat about 7 milUon erythro- 

 cytes are found in blood from the heart and central vessels and 

 8-10 million in blood from peripheral vessels (Jolly, '06). 



Jolly ('09) has given a series of determinations for the number 

 of red cells according to age and to locality of sample- — table 31. 



This table 31 shows the increase in the number of eryth- 

 rocytes with age and the loss in hemoglobin during the period 

 of dependence on the mother followed by an increase later. 



There is a fairly steady decrease in the 'Valeur globulaire" 

 (equal to the weight of the hemoglobin divided by the number 

 of erythrocytes) except for the period from 42-90 days — after 

 which there is little change. The cell production in the bone 



