74 
sulfur content as of accessory nature. In its physical properties, gen- 
eral chemical conduct, and decomposition products, hippomelanin 
shows a close resemblance to the artificial melanin produced by the 
action of tyrosinase on tyrosin. whereas it differs in certain respects from 
other melanins and epidermal pigments and the pigment phymatorhusin 
of malignant melanotic tumors. Up to the present, according to 
these authors, the chemical investigation of hippomelanin has dis- 
closed no fact at variance with the well-established hypothesis of the 
fermentative origin of melanin as the result of the action of tyrosinase 
on the cyclic complexes resulting from the degradation of the protein 
molecule. 
The principal sources of vegetable tyrosinase are certain of the 
higher fungi, especially many species of russula, such as the Russula 
delica (Bourquelot and Bertrand, ( 87 * 885 89 ), Agaricus meU-eus and 
Agaricus campestris (A on Furth and Jerusalem, 178 ), and wheat bran 
(Bertrand and Mutermilch, 65 ). The ink sac of the cuttle fish 
C Sepia officinalis ) and the hemolymph of the pupae of Deiciphila 
eupliorbise ( 178 , p. 161) are the chief sources of animal tyrosinase. 
In order to obtain a solution of tyrosinase from Russula delica it is 
only necessary to macerate the fresh fungus with chloroform water 
or with glycerin, or, as recommended by Bach ( 24 ), the tyrosinase of 
Russula delica may be precipitated from the aqueous extract of the 
fungus by means of 96 per cent alcohol. Young, sound fungi are 
ground in a sausage machine and 300 c. c. of the clear expressed juice 
is poured into 1.5 liters of 96 per cent alcohol. The precipitate thus 
formed is filtered off by means of a filter pump, washed with alcohol, 
and dried in vacuo over calcium chloride. The dried precipitate is 
now mixed with 300 c. c. of water, whereby only a small amount of the 
material goes into solution. The mixture is then filtered, an entirely 
colorless solution of tyrosinase being obtained. 
In this connection Bach ( 24 ) has observed that the activity of the 
tyrosinase solutions depends on the age and state of preservation of 
the fungus. Thus from three lots of the fungus (I, vouns;. unblem- 
ished fungi; II, older, more or less injured fungi; and III, putrid 
fungi) he obtained aqueous extracts, equal amounts of which acting 
on the same quantities of tyrosin. required the following quantities 
of 0.002 X. permanganate: 
1. 11. hi . 
37.8 c. c. 13.6 c. c. 8.3 c. c. 
The residue was then dried in vacuo or at once dissolved in 100 c. c. 
of chloroform water, in which case it was used at once, since aqueous 
solutions of the ferment are very unstable. By this mode of prepara- 
tion the tyrosinase is separated from the catalase which the fresh 
aqueous extracts of this fungus contain. These authors have found . 
