Ocroser 4, 1918] 
sented from the standpoint of the chemist—a 
discussion of the composition, properties, and 
toxicology of the remedies used for the control 
of agricultural pests. An effort was made to 
accumulate all available information from this 
viewpoint; the materials were classified accord- 
ing to active ingredient or derivation rather 
than according to use as had been heretofore 
done; and the subject presented accordingly 
as a three-unit course of lectures. 
A one-unit laboratory course was also offered 
by Mr. Miller, taking up in a practical way 
the most approved methods of preparation of 
pest remedies and demonstrating the signifi- 
cance of the simpler tests. The students were 
divided into groups and each required to pre- 
pare the commoner preparations which may be 
made on the farm, and were given an insight 
into the underlying principles of commercial 
manufacturing methods. The use of elab- 
orate apparatus was consistently avoided, only 
such utensils and measuring devices being 
used as would be found on the average Cali- 
fornia ranch. It was thought that if the 
students were taught the fundamentals of the 
various processes without any unusual equip- 
ment, they would be better able to make use of 
whatever equipment, simple or elaborate, would 
be provided them in later years of actual work. 
That this sort of instruction filled a want 
is evidenced by the fact that the enrollment 
increased from seven the first year to forty the 
fourth year that the courses were offered. 
In the fall of 1915, the laboratory was in- 
structed to undertake an investigation of. 
chemical means for the control of noxious 
weeds. Sets of experiments have been con- 
ducted in five localities, some of which have 
been under observation for more than two 
years. These investigations have furnished 
some very interesting data, both from the prac- 
tical as well as from the scientific standpoint, 
the results of which are to be soon published 
as a progress report. 
At first thought, it may seem strange that 
a study of herbicides was assigned to a chem- 
ical laboratory heretofore devoted to the study 
of insecticides and fungicides. A careful 
‘analysis, however, of the toxicological prob- 
SCIENCE 
331 
lems encountered in either case discloses a 
very close correlation of certain phases of the 
work. 
The accumulation, classification, and other- 
wise making available of an accurate and com- 
plete knowledge of the source, manufacture, 
composition, and properties of the poisons used 
for the control of insects, fungi, weeds and 
other pests is work for which the chemist has 
been trained. When any of these poisons are 
to be used upon vegetation for the control of 
insects or fungi, it is fully as important to 
know their action on plant tissues as their 
action on the pest, in order to ayoid the use 
of any remedy which may seriously injure the 
plant. Certain of these poisons can be used 
at certain times of the year only, or upon 
certain plants only; others are suitable for 
use under restricted climatic conditions. 
Some of these facts are directly applicable to 
the problem of weed control by means of chem- 
icals. The materials to avoid in the first case 
may be just the ones to use in the latter case. 
These observations may be well illustrated by 
referring to some of the results of this lab- 
oratory’s herbicide investigations. It is a 
well-known fact that soluble arsenic (except 
in very small amounts) is not permissible in 
any spray which is to be applied to cultivated 
plants on account of the danger of foliage in- 
jury; a completely soluble compound of arsenic 
was found to be the most effective of any 
chemical tried for the destruction of weeds. 
Unpublished experiments by Mr. E. R. de Ong 
and the writer, testing the action of petroleum 
oils on foliage, indicated that the constituents 
of petroleum distillates which are capable of 
removal by refining with sulfuric acid are very 
much more toxic to foliage than other con- 
stituents; a by-product of oil refineries, con- 
taining these highly toxic constituents, was 
found to be a very effective herbicide. 
Quite recently this laboratory has been 
called upon to analyze a number of squirrel, 
gopher and rat poisons and to pass on their 
respective merits, and to answer letters on this 
subject which were referred from other de- 
partments. 
It is thus seen that the scope of activities 
