398 The Botanical Gazette. [Oc 
was not definitely ascertained; it does not, however, appear to be de- 
pendent upon the currents of water in the plant, but is much more 
closely correlated with the actual growth of the germs. 
Only truly parasitic bacteria appear to have power to penetrate the 
uninjured surface of plants, and not all of this class. 
The author does good service by clearly distinguishing between the 
resistance which plants in general exercise toward the inroads of bacteria, 
and the zmmunity which certain groups of plants are able to maintain 
toward bacteria that are pathogenic in closely related sorts. The abil- 
ity of plants to resist the attacks of bacteria is due to both physical 
and chemical causes. Of the former are “the epidermal and cortical 
resistant tissues, matured and thickened cell walls of the inner tissue, 
exclusion by gummy exudates, etc.,” and of the latter “the chemical 
reaction of the juices, the unfavorable conditions of nutrition, the ac- 
tion of the living protoplasm, etc.” “The whole question of immun 
ity of plants from bacteria is much more closely related to the same 
question as regards fungi than it is to the subject of immunity as seen 
in the animal kingdom.” 
cribed to bacteria but the causal relation stil! uncertain (nine gigs 
en by Dr. 
his list of 
corn blight (Burrill), rot of hyacinth (Heinz), wet rot of potato ein? 
Of the remaining eight of Russell’s first list, three are anor 
excluded by Migula, and five are American and evidently unknow? © 
him. 
Most of the work in the study of bacterial disease 
been done by Americans, and it is gratifying to have’ an 
tant paper added upon the subject, also by an American. 
Minor Notices. -  Sacchat- 
A summary of the species of true yeasts, the spore Oe of the 
omyces, twenty-two in number, is given in the August 80°" — 
American Naturalist, by J. Christian Bay. lants, deliv: 
A LECTURE upon combating the fungous diseases a B. T. 
ered before the Massachusetts Horticultural Society a ology. has | 
loway, Chief of the U.S. Division of Vegetable ete of the 
cently been distributed. It is an instructive presentation Hah 
ject. ee 
?Micuta: Kritische Uebersicht derjenigen Pflanzenkrankhelteh — : 
geblich durch Bakterien verursacht werden. Semarang, i oe 
s of plants ™ 
other impor 
