1886.] BOTANICAL GAZETTE. 245 
with the narcotic above referred to were still susceptible. The 
writer made many experiments with the same poison, which were 
also negative in their results. Law has published experiments 
with swine plague from which he claims positive results, but the 
number of animals operated upon is too limited to be at all con- 
elusive, even if the details of the experiments were satisfactory, 
which is not the case. Quite recently in our experiments pigeons 
have been granted a very complete immunity from the effects of 
swine plague virus by treating them with cultures of the microbe 
in which all living organisms had been previously destroyed by 
eat. Up to this time, however, our experiments with pigs have 
only given negative results. 
Although there are still some points in connection with this 
subject which greatly need experimental elucidation, it is believed 
that the theory developed in this paper is in accordance with 
the facts so far demonstrated. The problems of immunity have 
long been considered impenetrable mysteries, and if this theory 
does not prove in all respects correct it is hoped that it may at 
least be of some service to other investigators. 
BRIEFER ARTICLES. 
Dr. Gray’s letter to the Botanical Club.—T> the Botanical Club of the 
A, A. A. §., at Bufalo: I am unable to attend the ensuing meeting of the Asso- 
ciation. But wishing to manifest my interest in the Botanical Club, and to 
show that I am not altogether an idler in the camp, I send herewith two small 
papers,* containing the result of some recent systematic work upon two familiar 
nera. 
would be much more readable than the papers themse 
prefatory to the essay on Dodecatheon will sufficiently explain that undertaking, 
and the result, which has given me no small satisfaction. For we have always 
felt confident that there were distinct western species, although I have never 
till now found a clew to lead toward the extrication of the various forms. 
ei ee ee ee es ee 
that on Violets in the next 
*The paper on Dodecatheon published in this issue, and 
