1921] PACK—JUNIPERUS 39 
MeEtHops.—As it has been shown that catalase activity increases 
with after-ripening of the dormant-embryo seeds (6, 10), catalase 
activity was chosen as the first standard. Germination, the produc- 
tion of independent seedlings, was selected as the final standard. 
Great care was found necessary in the preparation of material and 
the manipulation of the catalase apparatus. As the berry has a 
high catalase activity, every trace of fruit was removed before 
grinding. The grinding was carried out under similar conditions, 
and with a definite amount of water and no. 2 sand per unit weight 
of seed material. The dioxogen was neutralized with N/1o NaOH 
at the time of using. All determinations were made with the 
bath at 25°C., and the drive wheel of the apparatus regulated to 
make 30 revolutions per 10 seconds. No explanation is needed for 
germination as a standard. 
ForcInc aGENTS.—Among the common forcing agents tried on 
the juniper seeds were high temperatures, alternating tempera- 
tures, removal of coats, hydrogen peroxide, dilute acids, carbon 
dioxide, light, soil, mercuric chloride, ether, and oxygen. The 
first seven of these had very little effect on the catalase activity 
and did not force germination. While the treatments with mercuric 
chloride, ether, and oxygen did not force germination, each had its 
influence upon catalase activity. 
CROCKER and HARRINGTON, in an unpublished work at the Seed- 
testing Laboratories of the Bureau of Plant Industry, have found 
that HgCl, was a good forcing agent for Johnson grass. Juniper 
seeds were sterilized and put into flasks containing the following 
concentrations of HgCl,. After 24 hours the excess of liquid was 
poured off. The results are given in table V. These data, as 
well as those obtained by grinding the seeds for catalase activity 
in the same concentrations, show that HgCl, reduced catalase 
activity in the higher concentrations. None of the seeds treated 
with HgCl, germinated. 
In studying the effect of ether, seeds were sterilized, put Eto 
Petri dishes without covers, and exposed to air containing various 
amounts of ether by sealing in g liter cans. After a certain exposure 
the seeds were removed, aired, and placed to germinate. Table VI 
gives the catalase activity for seeds that were exposed to ether 
