CERTAIN SPECIES OF MuUcoR 259 
A series of sixty-five numbers of Mucor (including all the 
species of Mucor collected with the exception of Mucor botryoides) 
was tested for their ability to ferment a dextrose, peptone solution: 
(dextrose 10 per cent., peptone 0.1 per cent.) with positive results, 
except in the case of Mucor Ramannianus. 
Because certain organisms have the ability to change tyrosin, 
by the production of an enzyme, into a dark-colored compound, 
often accompanied by the production of a brownish black precipi- 
tate, it was decided to use this organic compound with a series 
of mucors. For this experiment a solution of the following com- 
position was employed: maltose 2 per cent., peptone 0.1 per cent., 
_ tyrosin 0.015 per cent. (I gm. tyrosin to 6,400 c.c. of solution). 
The same mucors which were used in the preceding experiment 
were also employed for this series. The results may be 
given in the following brief manner. Four (Nos. 22, 36, 57, 
and 67) were discarded on account of bacterial contamination. 
In Nos. 4, 5, 6, and 72 there developed an apricot yellow 
(Ridgway) submerged mycelium, the color being due to yellow 
globules in the hyphae. The following showed a slight pro- 
duction ‘of yellow color in the submerged hyphae: Nos. 1, 
2.5 9. 6; ET, 12,0513; 1 38) 16, 18) 1G, 20, 25) 28, ee oe 
31, 32, 33, 37, 38, 39, 42, 43, 56, 58, 60, 74, and 76. No 
color formation was found in Nos. 2, 10, 23, 24, 30, 34, 41, 44, 
45, 46, 47, 48, 49, 50, 51, 54, 59, 61, 68, and 70. There was a 
marked coloration of the solution, with the formation of a dark 
brown precipitate, in Nos. 26 (Mucor griseosporus) and 73 (Mucor 
coprophilus), the color of the solution in each case being dark 
reddish brown. In Nos. 34, 44, 51, and 61, the solution was 
colored pale brown, and a dark brownish black precipitate was 
formed. In Nos. 40 and 63 (both Glomerula repens) there was a 
brownish tinge to the solution, and the aerial growth was distinc- 
tive in that it was pinkish buff (Ridgway). 
[To be concluded.| 
