376 Mr. Hatchett's Experiments on Zoophytes, 



heated to 21 2° of Fahrenheit, till it became perfectly hard, 

 brittle, yellow, and semi-transparent, like horn. 



The albumen, in this state, was digested during eight days in 

 boiling distilled water, which was occasionally renewed, in pro- 

 portion to the evaporation. 



In a few hours after the commencement of the digestion, the 

 transparent horny pieces of albumen were softened, and became 

 white and opaque, exactly like albumen recently coagulated ; 

 but, after this, no farther change was observed. 



At the end of eight days, the water in which the albumen had 

 been digested was examined, and was found exactly to resemble 

 that afforded by quill, nail, and tortoise-shell ; for the trans- 

 parency of it was not disturbed by the tanning principle, 

 although nitro-muriate of tin produced a faint white cloud.* 



As far, therefore, as could be ascertained, by long digestion 

 in boiling distilled water, and by the effects of the re-agents, 

 albumen was proved to be very similar to tortoise-shell, and 

 many of the other substances previously noticed ; but the close 

 resemblance, or rather indeed identity, of albumen with those 

 bodies, will be placed in a stronger light, by the enumeration 

 and comparison of their other chemical properties. 



As I have, in the former part of this paper, had occasion to 

 mention the gelatin obtained from the Sponges and Gorgonice, 

 it is not necessary here to repeat those remarks, neither is it re- 

 quisite that I should enter into any minute account concerning 



* When infusion of oak-bark is added to recent liquid albumen, it immediately 

 forms a precipitate ; and nitro-muriate of tin does not produce any effect till some 

 hours have elapsed. B ut after coagulation the reverse takes place; for the water in 

 which coagulated albumen has been long boiled, becomes turbid by the addition of 

 nitro-muriate of tin; and is not in any manner affected by infusion of oak-bark. 



