456 MAMMALIA— PHYSIOLOGY 



and the volume of (red) corpuscles. According to Schmaltz, blood 

 with a specific gravity of 1,059 has 100 per cent of hemoglobin, that 

 with a specific gravity of 10,575 has 90 per cent hemoglobin, while 

 blood with a specific gravity of 1,049 ^^^^ have a hemoglobin content 

 of but 60 per cent. 



Blood has an alkaline reaction; this is at a maximum after meals 

 as the acid gastric juice is then in the stomach. The alkalinity is at 

 a minimum after exercise because of the HCO2 formed by contrac- 

 tion of the muscles. Blood has a salt taste and a faint smell. 

 Coagulation of blood is promoted by heat and standing, and re- 

 tarded by cold and the salts, sodium phosphate, sodium citrate and 

 magnesium phosphate. 



Blood consists of erythrocytes (red corpuscles), leucocytes 

 (white corpuscles), platelets, hematokonia or blood dust. Salt 

 solution swells the corpuscles and pure water will dissolve out 

 hematin from the red ones. Water has no action on the white 

 ones. We consider the red blood corpuscles as dead and the white 

 ones as very much alive. 



"Thrombocytes, usually spindle shaped, occasionally spherical, 

 are found in all of the vertebrates except mammals, in which only 

 thromboplastids (minute, cytoplasmic platelets) are found. Both 

 thrombocytes and platelets are associated with the clotting of the 

 blood. Lymphocytes are uniformly present in all classes of verte- 

 brates. Monocytes or, large mononuclear leucocytes, are also 

 uniformly present in all vertebrates. In man the neutrophilic leu- 

 cocytes predominate numerically." (A. B. Dawson.) 



The proportion of white to red corpuscles is as i : 300 or as 

 I : 500. There are many more white corpuscles shortly after meals. 

 The reds vary in number as one goes from sea level to the mountains. 



Size of reds Number of reds 



Animal in microns in i cubic mm. 



Elephant 9. 



Man '].i-i.^ 5,000,000 



Monkey 7.0 6,355,000 



Guinea Pig 7.48 5,859,000 



Dog 7.2 6,750,000 



Horse 5.58 7,403,000 



Cat 6.2 9,900,000 



Spanish Goat 4.25 19,000,000 



Napu Deer 2.0 



(From RoUett and Bethe in Bohm-DavidofF-Huber's Histology, W. B. Saunders Co.) 



