15 
quantity of the expressed residue corresponding to nearly 2 grams 
of dry matter, after being washed well and again expressed, was sus- 
pended in 20 cc. water and 10 ce. hydrogen peroxid added; in fifteen 
minutes 31 cc. of oxygen were obtained.. This shows that a solution 
of 0.5 per cent sodium carbonate did not extract all the a-catalase even 
in two days. 
It is more difficult to prepare the a-catalase free from peroxidase 
when using green tobacco leaves than when cured and fermented 
leaves are used, since it takes a long time to wash out the peroxidase 
from the pulp prepared from the fresh leaves. For example, 30 ce. 
of turbid, not filtered, juice prepared from tobacco leaves was mixed 
with ten times this quantity of water and filtered after standing fifteen 
hours, leaving a green residue in the filter, which even after pro- 
longed washing yielded the reaction for peroxidase, while that for 
oxidase had ceased to be produced in the wash waters after a short 
time. 
Water alone dissolves only traces of a@-catalase at 20° C., while 
prolonged action of water at a moderate elevation of temperature 
gradually splits off #-catalase, the process being favored by adding a 
small proportion of sodium carbonate. 
The following test shows that even very large quantities of water 
alone do not extract a-catalase to any noticeable extent. Two grams 
of finely pulverized cured tobacco were extracted for four hours with 
40 cc. of water at 20° C. and the residue washed until the filtrate was 
nearly colorless. This extracted tobacco yielded in fifteen minutes, 
upon the addition of 5 cc. hydrogen peroxid and 20 cc. water, 42 ce. 
oxygen. Two grams of the same tobacco were now extracted with 
1 liter of chloroform water for eighteen hours. The powder yielded, 
after washing under the same conditions as before, 40 cc. oxygen. 
It seems strange that neither Scheenbein nor Jacobson observed that 
the property of catalyzing hydrogen peroxid may be due to a soluble 
as well as toan insoluble substance. Schcenbein mentions only once— 
without, however, altering his opinion that the enzyms were the cause 
of that catalysis—that the filtered extracts of certain vegetable mat- 
ter show much less power of catalyzing hydrogen peroxid than the 
unfiltered. Jacobson also used, in his experiments mentioned above, 
the crude turbid extracts, but not purified enzym preparations. He 
used, for instance, an emulsion prepared from crushed almonds instead 
of purified emulsin. 
The following tests leave no doubt that the transformation from the 
insoluble to the soluble catalase really can take place. Sweated tobacco 
rich in a@-catalase was finely pulverized, repeatedly extracted with 
chloroform water’ at the ordinary temperature, and, when /-catalase 
‘Care must be taken in the application of chloroform water as an antiseptic that a 
full saturation is preserved, otherwise certain microbes will gradually develop. 
