24 Proceedings of Royal Society of Edinburgh. [sess. 
the two heat precipitates, that appearing at 50° C. was the more 
abundant, and, moreover, the coagulation occurred more sharply. 
From the solution of the original precipitate (Ppt. A) a white 
flocculent precipitate was thrown down by the addition of acetic 
acid. After removal of this precipitate by filtration, the filtrate 
when heated threw down a coagulum at 50° C. 
Another portion of the solution of Precipitate A, after being heated 
to 50°-55° C. and the coagulum filtered off, yielded a precipitate 
upon the addition of acetic acid. 
The original precipitate therefore obtained from the splenic extract 
by half saturation with ammonium sulphate consisted of at least 
two proteid bodies insoluble in that degree of concentration of the 
salt, but which were soluble in more dilute solutions. One of 
these substances coagulates at 50° C., and is not precipitated by 
acetic acid. The second proteid coagulates at 60°-70° C., and is 
thrown out of solution by acetic acid. 
These two proteids probably correspond to those described 
by Gourlay * as occurring in the spleen, viz., a cell globulin 
coagulating at 49°-50° C., and a nucleo-proteid coagulating at 
57°-60° C. There is a considerable discrepancy between the co- 
agulation point of Gourlay’s nucleo-proteid and that of my second 
substance. This possibly may be accounted for by difference in 
nature and concentration of the saline matters in the solution. 
Gourlay used a 5 per cent, solution of magnesium sulphate to make 
his extract, and examined that extract to determine the coagulation 
points. At the same time I found that this proteid did not coagulate 
sharply. The fluid began to grow opalescent at 60° C., but distinct 
flocculi would not separate out, even when kept for a considerable 
time at 60°-65° C. The formation of flocculi only became apparent 
after the temperature had been allowed to rise to 70° C. 
Having thus determined the existence of two proteid bodies in 
the solution of Precipitate A, these were separated from the main 
bulk of the fluid by the following method : — 
The fluid was heated on the water-bath to 50° -55° C., and 
maintained at that temperature for half an hour. It was then set 
aside for twenty-four hours, so that the fairly copious coagulum 
which had formed might settle to the bottom of the vessel. The 
* Journal of Physiology, Cambridge, 1894, vol. xvi. p. 23. 
