ol 
gen peroxid, 107.2 cc. oxygen in fifteen minutes, and was relatively 
rich in a-catalase. The stalk of the tobacco plant is about as rich in 
this enzym as the leaves, but the fine roots contain less. Only one 
comparative test was made on this point, however. In the flowers 
(air dry) of the tobacco plant hardly any f-catalase is found, but con- 
siderable a-catalase. 
Besides Phanerogams from different families, ferns, mosses, liver- 
worts, and higher and lower algze, as well as fungi, were also tested 
with positive results. It may be mentioned that vegetable cells die 
quickly in a 0.5 per cent solution of hydrogen peroxid, while their 
catalase is much more slowly injured. 
Suitable data which would allow the investigator to calculate the 
absolute weight of catalase from a certain volume of oxygen developed 
in a given time and at neutral reaction are thus far not known; hence 
the volumes of oxygen given off by different objects can have only a 
relative value, serving for purposes of comparison. ‘This is also the 
reason why these volumes were not reduced to normal pressure and 
0° C.' The following tests with leaves, fruits, and seeds were carried 
on at the request of the writer by Mr. D. W. May. Eight grams of 
the leaves in the fresh state were crushed to a pulp, with the aid of a 
little sand and water, before the hydrogen peroxid was added, while 
two grams of the seeds in the air-dried state were finely pulverized, 
shaken up with 50 cc. of water, and the mixture left in the ice box 
overnight for extraction. The filtrates were gradually mixed with 
5, 10, or even more cubic centimeters of hydrogen peroxid, as the 
degree of activity in special cases demanded, while the washed residue 
was suspended in from 50 to 60 cc. water before the hydrogen peroxid 
was added. 
Cubic centimeters of oxygen developed by different leaves. 
10 min- 15 min- 20min- | 25 min- 
i ee. utes. utes. utes. | utes. 
— _ } —_——_ = | 
| j | 
Magnolia (Magnolia sp.) ....--.....---..- 47 92 129 163: (|... 25-e eee 
Holly Gilexisps). oe. > Poe con eae ese sacs 50 95 129) |o.232..-4-- ae 
Clover? (Trifolium repens)...........--.. 98 129 176 218: | 22 = eee 
Cotton (Gossypium herbaceum).......... 49 102 157 209 |... ee 
BOSC] (RGED SD2) scot a6 S22 sarees ne 52 106 156 202 252 
SPLHCCUhICED SPs) 522250 aoose eee esac ese: 56 107 | 148 |... 95-5325 -| 43> eee 
1Jt may be mentioned, however, that the temperature of the laboratory ranged generally from 16° 
to 22° C. and 1 .1e barometric pressure from 746 to 771 mm. 
2 Clear filtrates of the diluted juices of the leaves of rose and clover were also prepared and tested 
but 8-catalase was absent. 
