506 [March 26, 



serum when subjected to oxygen gas, when acetic acid was added to 

 it, although another portion of the same serum had refused to 

 yield it without that addition. In this experiment the acetic acid 

 should he added until the serum is either neutral, or produces a 

 slightly acid reaction on test-paper. Care must he taken in these 

 experiments to prevent the temperature rising too high, for a coagu- 

 lation then takes place. If hlood-cells he present in the serum, the 

 addition of acetic acid attacks the cells in preference to the alkalies 

 of the serum ; and on subsequent exposure to a temperature of 100 

 F. during the period it is under the influence of oxygen, the whole 

 is transformed into a semisolid mass. 



It is a curious fact that serum which has been placed on a dia- 

 lyser for the removal of the salts by Graham's method was not im- 

 proved in its power of producing fibrin, over serum which had not 

 been submitted to that treatment previous to its oxidation. On 

 the other hand, albumen purified from salts by Graham's method, 

 and then subjected to the influence of oxygen, yielded the largest 

 amount of fibrin. By this method it is most probable that I should 

 have been able to have transformed the whole of the albumen into 

 fibrin, had not an accident unfortunately brought the experiment to 

 a termination. Nevertheless, although the experiment was not con- 

 tinued long, half the albumen was changed into fibrin. 



When experimenting upon albumen nearly free from alkalies and 

 alkaline salts, great care must be taken to keep the temperature as 

 low as possible. I found that a temperature between 80 and 90 F. 

 was the best, for above 98 the albumen had a very great tendency 

 to coagulate. 



"When albumen was placed in a tube which contained about an 

 equal bulk of oxygen, and in which a platinized platinum wire 

 had been inserted extending the whole length of the tube, to facili- 

 tate the action of the oxygen on the albumen, and which tube was 

 subsequently sealed and placed in a water-bath of 98 F., no fibrin 

 made its appearance even after the lapse of 36 hours, but in its 

 place a small quantity of an amorphous material subsided to the 

 bottom of the tube. When, however, a tube of similar size was 

 filled with albumen having free access to the air, and then placed 

 on the same water-bath for an equal length of time, on the sur- 

 face of the albumen which this tube contained small masses of 



