196 ANIMAL AMIDES. 



The differences between these results are considerable, proba- 

 bly depending upon the presence of some foreign matter. The 

 mean of the five is as follows : 



Carbon, . 52-05 



Hydrogen, . 7-28 



Azote, . 17-66 



Oxygen, . . 23-51 



100-00 



Before we can draw any conclusion from these analyses we 

 must know the atomic weight of fibrin. Berzelius made some 

 experiments to show that its atomic weight may be determined, 

 but has stated no numerical results. Mulder made several salts 

 of fibrin and subjected them to analysis. It will be worth while 

 to state the results which he obtained. 



1. Fibrate of copper. When sulphate of copper is added to a 

 solution of fibrin in caustic potash, green flocks of fibrate of cop- 

 per precipitate. This salt being analyzed gave, 



Fibrin, . 798 or 64-35 = 1 atom. 

 Oxide of copper, 62 or 5' = 1 atom. 

 3. Subsesqui-Jibrate of lead. It was obtained by mixing sub- 

 acetate of lead with fibrate of potash. It was composed of, 

 Fibrin, . 38331 or 63.896 = 1 atom. 



Oxide of lead, 5599 or 21- = 1 atom. 



3. Fibrate of silver. It was prepared by dissolving fibrin in 

 acetic acid and mixing the solution with nitrate of silver. It 

 was composed of, 



Fibrin, . 6984 or 62-52 = 1 atom. 



Oxide of silver, 403 or 3-625 = J atom. 



The mean atomic weight of fibrin deduced from these three 

 analyses is 63-588. 



4. Mulder passed a current of dry muriatic acid over dry 

 fibrin, till no more absorption took place, and then passed through 

 the apparatus a current of dry air till muriatic acid fumes no 

 longer made their appearance. 1112 of fibrin by this treat- 

 ment increased in weight 80. Hence the muriate of fibrin was 

 composed of, 



Muriatic acid, 80 or 4-625 = 1 atom. 

 Fibrin, . 1112 or 64-287 = 1 atom. 

 The mean of all these analyses gives us 63.76 for the atomic 



