1897. | Botany. 901 
WE have received notice of the recent formation at New Orleans of 
“The Louisiana Society of Naturalists” with Prof. J. H. Dillard, of 
Tulane University, as President, and Mr. E. Foster, Secretary. The 
Society has already about 45 members, nearly all of whom are workers 
in some branch of natural science. It proposes to work up the fauna 
and flora of the State in a systematic manner, a task never before at- 
tempted. One has only to look at the map of Louisiana—possessing 
the mouth of one of the largest rivers in the world, numerous bayous, 
vast salt and freshwater lakes, large islands and bars, extensive swamps 
and forests—to see what grand possibilities are in store for this society 
if its members will study geogtaphical distribution in the broad and 
yet detailed way in which it is done by the Biological Survey of the 
Department of Agriculture. We hope to receive reports from time to 
time of the results achieved by the society. 
General Notes. 
BOTANY. 
Pfaffs Observations on the Nature of Ivy Poisoning.— 
Considering the frequency of Rhus poisoning and the abundance of 
our two noxious species, it is remarkable that the exact nature of the 
irritant has so long eluded discovery. The most widely divergent 
views upon the subject have from time to time been advanced. Khit- 
tel, in 1858, regarded the poisonous principle a volatile alkaloid ; 
Maisch, in 1865, believed it a volatile acid; while Burrill at one time 
thought a bacterial germ might be the responsible agent. However, 
none of these observers has made a very satisfactory case, and it is 
-accordingly a matter of more than ordinary interest that the poisonous 
principle has at length been isolated by Dr. Franz Pfaff, of the Harv- 
ard Medical School. As Dr. Pfaff’s preliminary article’ upon the sub- 
ject is published in a medical journal and may, therefore, escape the 
notice of biologists who are not also physicians, his results may be sum- 
marized in these columns. 
After a résumé of the investigations on Rhus poisoning, the fact is 
pointed out that skin irritants are, in general, rapid or slow in their 
* Journal of Experimental Medicine, II, 181-195, t. 10. 
