1880. ] Botanizing on the Colorado Desert. POT a 
Whether the lac is to be considered as an excretion or secre- 
tion is very much a matter of definition. If by secretion we 
mean a definite substance elaborated by the organism for a defi- 
nite purpose, this would appear to be a true secretion. On the 
other hand, once secreted it probably exerts no further internal 
function in the organism, and is in so far an excretion. In the 
Same sense, hair, nails, epidermis, etc:, continually discarded 
by the organism, might be considered excretions. However we 
may regard it, it is probably a normal product of the vital activity 
of the lac insect. 
A somewhat striking objection against this theory is, that it is 
against analogy, that a well-marked resin should be the product 
of animal life. But so also is the production of wax by the bee 
against the same analogy, and yet it has been proven that bees 
confined to an exclusive diet of sugar will produce wax formed 
by their own vital processes, and any philosophical distinction 
between wax and resin in this particular would, I think, be diffi- 
cult to establish. 
In conclusion, I would again reiterate that Iam by no means 
certain that the question of the origin of the lac has not been 
settled by observers more directly interested in natural history, 
but if so, our chemists and encyclopedists have been slow to find 
out the facts, and our most recent authorities, with few exceptions, 
adhere to the exudation theory. If this communication has the 
effect of bringing to notice previous work, or gives rise to more 
complete investigations in the future, it will be as much as I can 
expect from it. 
70: 
BOTANIZING ON THE COLORADO DESERT. 
BY EDWARD LEE GREENE. 
Los : 
r February of 1877, by way of the stage road between San- 
Diego and Fort Yuma, I made a little expedition across the 
interesting region above named. A desert is not naturally 
supposed to be the most eligible locality, nor midwinter the ae 
best season for making botanical excursions, yet seldom hasa 
_ week’s recreation of that kind given me more satisfaction than 
that upon which I have preserved the following notes: 
In passing from west to east across Southern California, the 
