170 ANIMAL AMIDES. 



containing humin and sal-ammoniac, while an altered muriate 

 of protein is deposited. 



In concentrated sulphuric acid, protein swells into a jelly. 

 When this jelly is cut into pieces, and put into cold water, that 

 liquid removes the excess of acid, and the mass shrivels up into 

 a white sulphate of protein, which is insoluble in water. This is 

 the substance to which Mulder has given the name of sulpho- 

 proteic acid. Its characters will be given afterwards. When 

 protein is boiled with dilute sulphuric acid, it becomes purple- 

 coloured. 



Protein combines with alkalies and bases. With the alkalies 

 and alkaline earths, it forms compounds soluble in water, from 

 which it may be precipitated by the addition of alcohol. Its 

 compounds, with the earths and metallic oxides, are insoluble. 



Mulder analyzed three specimens of protein, the first obtain- 

 ed from fibrin, the second from albumen of eggs, and the third 

 from albumen of serum of blood.* Dr Scherer analyzed also 

 three specimens, the first from the crystalline lens of the eye, 

 the second from albumen, and the third from fibrin.f The fol- 

 lowing table exhibits the results of these analyses : 



Mulder. Scherer. Mean. 



1. 2. 3. 1. 2. 3. 



Carbon, 54-94 54-93 55-40 55-300 55-160 54-848 55-096 



Hydrogen, 6-95 7-07 7*16 6.940 7-055 6-959 7*022 



Azote, 15-83 15*83 16-00 16-216 15-966 15 847 15-948 



Oxygen, 22-29 22-17 20-34 21-544 21-819 22-346 21-752 



100-01 100- 98-90 100- 100- 100- 

 Mulder represents the constitution of protein by the formula, 

 C 40 H 31 Az 5 O 12 = 54-625. If we calculate from this formula, 

 we get 



40 atoms carbon, = 30- or per cent 54-93 



31 atoms hydrogen, = 3-875 ... 7-09 



5 atoms azote, = 8-750 ... 16-02 



12 atoms oxygen, =12-000 ... 21-96 



54-625 100-00 



Numbers which almost coincide with the mean of the six analy- 



* Ann. der Pharm. xxviii. 74. f Ibid. xl. 43. 



