IOIO The American Naturalist. [November, 
BOTANY.! 
The Flora of Chicago.?—In this clearly printed catalogue the 
authors have made a valuable addition to the list of local floras of this 
country. Very properly the catalogue is prefaced by a brief sketch of 
. H. H. Babcock, who did so much to'make known to the world 
the peculiarities of the vegetation of Chicago and its vicinity. Then 
follows an interesting chapter on the geology of the region covered by 
the catalogue. At the close of the chapter the matter is summed up 
as follows: ‘Though Cook county, Illinois, and Lake county, 
Indiana, have neither mountains nor valleys, no frowning cliffs nor 
rocky glens, they have an interesting geological history, the outcome 
of which is a very unique botanical area. ‘The rolling prairies, the 
river bottoms, the sandy ridges, the lake shore, the drift clay and its 
ravines, the sloughs among the ridges at the south end of the lake, the 
peat logs which are found in many places, the shallow ponds and 
sluggish streams, give a great variety of soil for native plants.” 
In this area there are catalogued 1,140 species and varieties of native 
plants, 182 of which have been introduced. The largest order is 
the Composite, with 170 species and 19 varieties. The next in order 
are: Cyperacez, 97 species and rọ varieties; Graminex, 85 species 
and 5 varieties. The largest genus is Carex, with 55 species and 15 
varieties. The Pteridophytes have 31 representatives. No attempt is 
made to enumerate the mosses, liverworts, fungi, etc. 
The conformation of the nomenclature to modern ideas, and the 
uniform *‘decapitalizátion ” of specific names, will commend this 
catalogue to the majority of the botanists of the country.—CHARLES 
E. BEssEy, 
The Action of Bacteria on the Rapid Souring of Milk 
During Thunder Storms.—That milk will sour with unusual 
rapidity during thunder storms is a theory very commonly held among 
dairymen, and probably is to a certain extent true, It has been stated 
by various writers that this is due to an oxidation of the milk by the 
ozone generated in the air at such times, the oxygen of the air being 
converted into ozone by the electrical discharges. 
1 Edited by Dr. Charles E. Bessey, University of Nebraska, Lincoln. 
2 The Flora of Cook County, Illinois, and a Part of Lake County, Indiana. By 
Wiliam K. Higley and Charles S. Raddin, In the Bulletin of the Chicago Academy of 
Sciences, Vol. II., No. 1, Chicago, 1891. 
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