70 
with Spitzer’s para-phenylenediamin-o'-naphthol reagent. It is 
therefore evident from these observations that the blood of these 
lepidoptera contains oxidases having the power of oxidizing guaiacum, 
Spitzer’s reagent, tyrosin, and the chromogen of the blood itself. 
Attempts to purify the tyrosinase of the blood of lepidoptera by 
precipitation with uranyl acetate according to Jacoby ( 225 ) failed. 
Yon Fiirtli and Schneider were able to separate it from the chro- 
mogen and from the crystalline substances of the blood by frac- 
tional precipitation with ammonium sulfate. The ferment thus 
purified gave with tyrosin a violet-colored solution, which after a 
short time became dark violet and finally black. It was also found 
to produce coloring matter with pyrocatechin (yellowish red) and 
hydroquinone (red solution becoming turbid and finally showing a 
considerable brown precipitate); a carmine-red solution of an iron 
compound of suprarenin, the blood-pressure-raising compound of the 
suprarenals, became dirty brown in color, whereas the control experi- 
ment showed no alteration. Oxyplienyl-ethyl aniin (Emerson) 
became yellowish brown and gave finally an olive-colored precipitate. 
On the other hand, it was found to have no action upon casein, indi- 
cating that the ferment is powerless to act on the tyrosin residues 
contained in proteid molecule. The nature of the black substance 
produced by the action of the tyrosinase of lepidoptera on tyrosin was 
also studied. Ten to twenty c. c. of a freshly prepared solution of the 
ferment, obtained from the lymph of from twenty to forty Deiciphila 
pupae, was brought together with a few decigrams of finely pulverized 
tyrosin and shaken vigorously in a shaking machine for four to six 
hours. In a short time the characteristic violet coloration appeared 
in the solution, and after a time a considerable black precipitate sep- 
arated, leaving the supernatant fluid clear and colorless. With fresh 
quantities of tyrosin this gave no further coloration. This material 
was then filtered off and washed with water, then with dilute hydro- 
chloric acid, then with hot water until chlorine free, and finally with 
alcohol and ether and dried to constant weight at 110° C. This black 
substance was found to be insoluble in water, alcohol, ether, and the 
common organic solvents and in dilute alkalis at room temperatures 
and in strong boiling hydrochloric acid. A small quantity of it 
melted with the purest sodium hydroxide from sodium gave rise to 
an unmistakable odor of indol and skatol. On analysis it gave the 
following numbers : 
Per cent. 
C 55.44 
H 4.45 
N 13.74 
corresponding to the following atomic ratios: 
N: H: C = 1 : 4.55: 4.77, 
