474 



Simon Heyiry Gage 



due to reagents, the corpuscles were examined in the serum of 

 the blood, without the addition of any reagent whatever, and 

 to avoid any possible error on account of the small amount of 

 blood in the 9 mm. embryo, the circulating blood was exam- 

 ined. All the examinations were made with a 2 mm. apo- 

 chromatic objective and an ocular X 12 " (Gage '88). 



Table showing the diameter and thickness of the red and of the ruhite 

 blood-corpuscles of the lamprey in the adult and larval condition ; 

 also the relative ntonber of red a7id white corpuscles, and the nutn- 

 ber of red corpuscles in a cubic millimeter of blood. 



The blood for measurement and counting was taken from 

 the heart of an animal just killed or from a pithing wound, 

 and mounted without the addition of any liquid. The cover- 

 glass was supported by a hair and sealed with castor oil. 

 Only undistorted corpuscles were measured. The averages 

 were obtained from twenty-five measurements in each case. 

 All measurements were made with a jV o^ tV homogeneous 

 objective, and a Jackson ocular micrometer, the valuation of 

 which was determined by using a Rogers' standard stage mi- 

 crometer. 



