210 
Journal of Agricultural Research 
Vol. II, No. 3 
into racemic acid or causes a production of an active acid of opposite 
polarity to the acid already present has not been settled. It has been 
shown (Hastings, Evans, and Hart) that the Bacterium lactis acidi doespro- 
duce enzyms, and it may be that these enzyms are one of the factors in 
the production of racemic acid, although it is more probable that, because 
of the very slowness of the enzymic action, the real factor is an increas¬ 
ing number of active bacteria of different types from the B . lactis acidi. 
The question whether B . lactis acidi or its enzym is the cause of the 
disappearance of active lactic acid and the appearance of racemic acid 
must be considered. It is known that lactic acid isolated from a lactose 
solution inoculated with B. lactis acidi is active in variety and not racemic. 
Even after prolonged standing, the lactic acid is found to be active. 
For this reason it is not believed that B. lactis acidi is the direct cause of 
this change. To determine whether the enzym of B. lactis acidi is the 
cause of this transformation, a solution containing active lactic acid, 
formed by inoculation with this organism and after several days treated 
with toluol, was allowed to stand for 2 months at 35 0 C. At the end of 
this time all of the lactic acid isolated was found to be active in variety, 
as shown by Table XXI. 
Table XXI .—Analysis of a solution of toluolated active lactic acid , showing active lactic 
acid 
Fraction No. 
Zinc lactate. 
Water of 
crystallization. 
Grams . 
~ 
Per cent. 
I. 
0. 1148 
12. 98 
2. 
. 4812 
12. 96 
3 . 
I. 0186 
12.99 
4 . 
I- 37 I 3 
13.06 
1 
Further, it was thought possible that the kind of lactic acid produced 
by B, lactis acidi might be influenced by temperature conditions. In 
order to test this, a lactose solution containing 3.6 per cent of lactose, 
1 per cent of peptone, and 10 grams of calcium carbonate to 300 c. c. 
of the solution was inoculated with this organism and put in the ice box. 
After 38 days the lactic acid isolated was found to be active in form 
(0.1303 gram of zinc lactate gave 13.04 per cent of water of crystalliza¬ 
tion) ; hence it is clear that low temperature does not change the direction 
of the reaction. 
The foregoing experiments lead to the conclusion that the B . lactis 
acidi examined or its enzym, either in the presence or absence of anti¬ 
septics, is not the direct cause of the disappearance of active lactic acid 
and the appearance of racemic acid. Probably the same conclusion is 
applicable to cheese curd. 
