1863.] 507 



fibrin were formed, which had an appearance identical with that of 

 blood-fibrin under the microscope, giving a conclusive proof to my 

 mind that, during the formation of fibrin by the action of oxygen on 

 albumen, a volatile constituent is formed and carried off by the 

 excess of oxygen which passes into the albumen in solution. 



The following are the chief physical and chemical properties of 

 the fibrin artificially formed by the action of oxygen on albumen : 



It has a lighter specific gravity than albumen, being always found 

 floating on the surface of the albumen, provided it is free and not en- 

 tangled or attached to the side of the vessel or platinized platinum 

 wire that has been inserted in the albuminous solution. 



It has a fibrinated appearance under the microscope, and is ca- 

 pable of being teased out into filaments in the same manner as blood- 

 fibrin. 



Acetic acid completely dissolves it after some time. 



Soda and potash cause it to swell up and dissolve. Concentrated 

 solution of ammonia, after the lapse of some hours, causes the fibrin 

 to swell up in a gelatinous mass, similar to that which occurs when 

 blood-fibrin is submitted to the same reagent. 



A hot or cold solution of nitrate of potash does not dissolve it 

 when it is digested in that menstruum for some hours. 



With Millon's test it becomes of a brick-red colour. 



With nitric acid a bright yellow colour became visible. 



Fibrin heated with hydrochloric acid gave a blue colour, and sub- 

 sequently dissolved, giving a blue tint to the liquid . 



An acid solution of acetate of lead caused both blood-fibrin and 

 fibrin artificially prepared to swell up and become translucent after 

 digestion for a certain period. 



III. " On Diffusion of Vapours : a means of distinguishing be- 

 tween apparent and real Vapour-densities of Chemical 

 Compounds." By J. A. WANKLYN and J. ROBINSON, Esq. 

 Communicated by Dr. FRANKLAND. Received March 10, 

 1863. 



The density of the vapour given off when a chemical compound 

 is heated is not necessarily the vapour-density of that chemical com- 



