BLOOD-CORPUSCLES 



gland is bright red. Inasmuch as the red color of the blood depends on 



the presence of oxygen in the red corpuscles, the loss of oxygen which 



occurs as the result of the katabolic processes in the gland changes the 



blood from red to blue ; but if the quantity of blood passing through the 



gland is so great that this change is much diminished, the red color 



of the arterial blood remains. 



Although oxygen is replaced 



by carbon dioxide in molecular 



katabolism, the quantity of 



oxygen lost in this process is 



not sufficient to produce the 



change from red to blue, on 



account of the great activity 



in the local circulation, which 



occurs during secretion. 



La king- of Blood. When 

 serum from the blood of one 

 animal is added to the blood 

 of another animal of a differ- 

 ent species, a curious phe- 

 nomenon is presented, called 

 the laking of blood. The red 

 corpuscles are broken up and 

 the hemoglobin appears in 

 solution, leaving the filmy remains called the ghosts of the corpuscles 

 to settle to the bottom of the vessel. This is merely a solution of 

 the coloring matter, which is freed from the stroma of the corpuscles 

 and gives the peculiar color to the solution. A phenomenon analogous 

 to the laking of blood was observed by Rollett. By alternately freezing 

 and thawing blood, he succeeded in extracting the hemoglobin. When 

 afterward warmed and liquefied, the solution was dark and transparent, 

 with the corpuscles entirely decolorized. 



BLOOD-CORPUSCLES 



In 1661, Malpighi, with the imperfect lenses at his command, dis- 

 covered the blood-corpuscles of the hedgehog. Leeuwenhock saw the 

 human blood-corpuscles in 1673 and described them in a communication 

 to the Philosophical Society in 1674. William Hewson discovered the 

 leucocytes about a century later. Neumann, of Konigsburg, and 

 Bizzozero, of Turin, described the blood-platelets about 1868. Since 

 that time, three varieties of corpuscles have been recognized in human 

 blood. 



c 



Fig. 13. Blood of Guinea pig, spread and dried on 

 glass cover, X 1450 (Sternberg). 



The corpuscles of the Guinea pig have the same form 

 as human corpuscles, but are a little smaller, measuring 

 about 3B ^j 5 of an inch (7 M) in diameter. 



