486 



[March 19, 



usually about a fourth part of the size of the corpuscle on which 

 they were fixed j but they varied considerably. Some were only 

 minute bright specks in the cell- wall j others were half or even two- 

 thirds as large as the corpuscle itself. Very rarely (in mammalian 

 blood) two such projections were seen j and as rarely a corpuscle 

 was devoid of any. 



The projections were commonly round or dome-shaped, bordered 

 with a deeply refractive outline. Frequently a minute, apparently 

 vesicular body could be seen within this outline, and then the pro- 

 jection presented a curiously hooded aspect (fig. 2, 5, 5). In a uri- 

 nary deposit from a lad twelve years of age, containing pus and blood, 

 nearly every blood-disk presented the hooded appearance after the 

 addition of tannin. 



The blood of the fowl, turkey, duck, and goose showed exactly 

 analogous phenomena with the same reagent (see fig. 3), 



Fig. 3. 



Blood of fowl after the action of tannin. 



The projection had sometimes the hooded character with a vesi- 

 cular body within ; sometimes the projection offered no such distinc- 

 tion of parts. It was situated indifferently on any part of the peri- 

 phery. In all the birds examined a second projection was as rare as 

 hi mammalia. 



Of fish, the dace, minnow, and carp were examined. The tannin- 

 solution produced a similar effect to that seen in the fowl with this 

 difference, that a large number of corpuscles had two projections 



