( 1203 ) 
lipolyticum a, which form acid from glucose, do not split. We likewise 
observe that the presence of acid also prevents decomposition of the 
fat by the lipase produced by the bacteria which do not form acid 
from glucose; this is distinetly to be seen by the narrowing of the 
fields at the points where the inoculation streaks cross. 
It would, however, be erroneous to draw the conclusion that in 
cultures where the fat is not decomposed by the formation of acids, 
lipase is neither secreted. That this enzyme is indeed present is 
proved by neutralising such a culture after addition of an antisep- 
ticum; already after some hours a distinct decomposition of the fat 
is to be observed; it is not, however, so vigorous as in cultures 
where no acid formation has taken place, although the microbes in 
cultures with glucose thrive often better than in those without it. 
But if caleiumearbonate is added to culture media containing glucose, 
the acids formed by bacteria are neutralised, the fat is then 
decomposed nearly as vigorously as in cultures containing no glucose 
and carbonate. These facts may be stated very simply as well with 
the help of fatted tubes as by means of plate cultures. 
At a certain degree of acidity fat is no more decomposed by the 
lipase, which was shown by a series of tubes filled with an increasing 
quantity of acid, in this case lactie acid, with a quantity of 
a culture of fat splitting microbes. It is found that the decom- 
position of the fat decreases as the rate of acid rises, and that it 
ceases entirely when the culture liquid is about '/,, N. acid. 
This acid-limit for the action of the lipase is the same for the 
enzymes of B. Stutzeri, B. lipolyjticum a, B. lipolytieum B, and 
of Oidium lactis. 
The lipase is rendered inactive as well by mineral as by organic 
acids, the former act more vigorously on the ferment than the latter, 
so that a lipase preparation, inactivated by mineral acids, after 
neutralisation is considerably less active than the same preparation 
treated with an equal quantity of an organic acid and subsequently 
neutralised. It is some time before the splitting power of the 
lipase is restored; this depends on the nature and the volume of the 
acid used. Whilst, for example, in a culture containing lipase, after 
acidification with lactic acid to */,, N. and subsequent neutralisation, 
the decomposition of the fat became already visible after one hour’s 
cultivation at 37° in a tube of neutralised culture, this lasted 6 hours 
when phosphoric acid of the same concentration had been used, the 
same culture conditions being observed. 
79% 
