71 
which is essentially the same as that obtained by Hofmeister for a 
whole series of pigments ordinarily called Melanine, to which belong 
the dark pigment of the hair, and of the skin, the choroid coat, mela- 
notic tumors, sepia black, and certain split products of proteids, such 
as Schmiedeberg’s melanine acid (melanin satire). In its physical 
properties, solubility, etc., and in its tendenc} 7 to yield substances 
having a skatol-like odor, on melting with alkali, it agrees closely with 
the melanins, and with a pigment obtained by Ducceschi ( 149 ) by 
oxidizing tyrosin with potassium chlorate in hydrochloric acid solu- 
tion. For other analyses of the black pigment of hair and feathers, 
see Hodgkinson and Sorby ( 213 ) . 
According to these authors (von Fiirth and Schneider) tyrosinase 
in its occurrence in the animal kingdom is by no means limited to the 
insects. They have also obtained it from the blood of the crawfish 
(Flusskrebse ) , and by refined methods it would doubtless be possible to 
recognize tyrosinase in the most widely differing classes of animals. 
Acting upon their suggestion, Przibram, of the zoological station at 
Trieste, found tyrosinase in the ink sac of the cuttlefish, Sepia 
officinalis. An extract of the washed epithelial lining of the sac gave 
with a solution of tyrosin first a very beautiful orange-yellow color, 
changing to sepia brown, and finally yielding a black precipitate. 
Yon Fiirth and Schneider are therefore of the opinion that prob- 
ably wherever melanotic pigments occur in the living tissues 
of the lower and higher animals they originate as the result of the 
action of appropriate enzymes on substances of aromatic nature. 
They point out in this connection that Salkowski and Jacoby have 
shown independently that tyrosin results from the autolj^sis of various 
animal tissues. It would seem likely therefore that in the formation 
of melanotic pigments two ferments are jointly concerned, one, an 
autolytic ferment capable of splitting off tyrosin or a similar aromatic 
complex from the protein molecule, and the other tyrosinase, which 
transforms the tyrosin into melanin. To determine whether tyro- 
sinase occurs in melanotic tumors offers an interesting and important 
field for further investigation. 
Gessard ( 184 ) has obtained tyrosinase from the glands of the ink sac 
of the cuttlefish ( Seiches ) and calamary ( Colmar ), and in 1904 this 
same author ( 19 °) showed that the coloration of the integument of the 
green fly ( Lucilia Caesar L.) is due to the action of tyrosinase. The 
larvae of the fly are white, and from them this author was able to 
obtain tyrosin in crystalline condition, as well as to demonstrate the 
presence of tyrosinase. In the course of their metamorphoses these 
larvae exhibit a succession of colors similar to those shown by a solu- 
tion of tyrosin when acted on by tyrosinase, until finally the insect 
attains the full iridescent green color of the fly. When the white 
pupae are kept in a vacuum the ferment is inactive and they remain 
