Egg plant rots 
285 
in a mortar, 125 cc of water were added and after having been allowed 
to stand for 6 hours, 312 cc of liquid were expressed. 800 g of rotted 
fruits were used, to which 50 centimeters were added, and from this 
576 cc of liquid were extracted. 
Since precipitation with strong alcohol is one of the commonest 
methods employed 0 in securing enzymes it has been used in these experi¬ 
ments. To each of the liquid extracts was added 4 volumes of 95 per 
cent alcohol. This caused the formation of a gummous precipitate, pro¬ 
bably carbohydrate in nature, but as yet unknown, which included or 
carried down with it the enzyme present. The precipitates from the Egg 
plant extracts were brownish black and from the Rhizoctonia mycelium 
grayish. The color imparted to the fruit extract precipitates was due, 
beyond doubt, to the presence of an oxidizing enzyme, laccase, which 
Kastle (20) [see p. 63] finds to be readily obtained in aqueous solutions 
from Egg plant fruits. Bach and Chodat(20) [see p. 118 to 120] have 
showed that this enzyme is composed of two distinct substances, an 
oxygenase — that is a substance which forms a peroxyde by taking 
up oxygen and which is replacable by hydrogen peroxide — and a per- 
oxydase, which activates this peroxide or the hydrogen peroxide added. 
After 24 hours the material was filtered through filter paper and the 
precipitate was washed with 95 per cent alcohol and permitted to air dry. 
Meanwhile, test tubes containing a small amount of sterile distilled water 
had been prepared. Cylinders of tissue from Egg plant fruits, made with 
a six millimeter cork borer, were placed in these test tubes, using every 
care to preserve aseptic conditions. Cylinders of Carrots, Irish Potatoes, 
and Pears were prepared in the same way. An attempt was then made 
to redissolve the dried precipitate in a small amount of water. Water 
was found to have no appreciable effect upon the coagulated gummous 
material in this precipitate. Nevertheless quantities of the partially dis¬ 
solved precipitate, varying from a few drops to several cubic centimeters, 
from normal and rotted Egg plants and from the mycelium were added 
to the tubes containing the cylinders. Within 13 hours the Egg plant 
cylinders were completely disinteregrated by the enzyme isolated from the 
decaying fruits and from the mycelium. The enzyme from both sources 
seemed equally active. Since it has not been possible to isolate the 
enzyme free from gums, no quantative results were obtained, nothing is 
known of the time relations and the effects of temperature, acids, alkalies 
etc. on the action of the enzyme. 
No evidence of softening occurred in the cylinders treated with the 
extract from healthy fruits. The cylinders, used as checks, remained firm 
and sterile. Carrots, Pears and Irish Potatoes showed after several 
days no evidence of enzymotic activity. A second set of cylinders was 
prepared with the same result. 
Tissues which had been acted upon by the enzyme was examined 
microscopically and it was found that the cells were intact, the middle 
lamella having been dissolved thus permitting the cells to become dis¬ 
sociated. The enzyme must therefore be one of the cytolytic enzymes, 
pectinase. Cytolytic enzymes are not at all uncommon in various 
1) Consult Euler, H., General Chemistry of the Enzymes, I—IX, 
p. 319, 1912. 
