1894.] - Botany. 427 
bacteria are thus known at present, namely, (1) Bacterium aceti (Kiitz.) 
Zopf, (2) B. pastewrianum Hansen, and (3) B. kiitzingianum Hansen. 
The cardinal temperatures are: Minimum for (1), 4°-5° C; for (2), 
5°-6° ©. Maximum is for all of them 42°-43° C, and optimum 34° 
Morphologically, these species consist of (1) long cells, (2) swollen 
cells, and (3) chains of short bacula. By 40° C-40°, 5 C pure cultures 
were in good development, during which some of the cells of the 
chains grew very long, and in twenty-four hours, there was a typical 
vegetation of long cells, totally different from the original culture. If 
this new culture is exposed to a temperature of 34° C, the original 
chains are again formed. The long cells measured 200» and more; by 
34° C ; they first swell in one or more places, sometimes assuming ball 
shape (diam. 11), then they are divided into typical chains. Nägeli 
regarded the long and the swollen cells as abnormal forms. 
When we speak of the influence of outward agencies upon the life- 
activity of organisms like those mentioned above, we have generally 
described the influence in its action only upon one feature of such 
activity. It is not at all sure that the cardinal temperatures of fermen- 
tation are identical with those of the life of the yeast, or with those of 
the cell-division or spore formation of the latter. We know that the 
cardinal temperatures of germination, transpiration, respiration, assim- 
ilation, geotropism, heliotropism, hydrotropism, rheotropism, etc., ete., 
in “higher” plants are not always identical. In the instance men- 
tioned above, we see that the cell-division hasits cardinal temperatures, 
a conclusion which we may draw from the observations. We further see 
that bacteria are more polymorphus than is suspected, and that a new 
road is open for investigation which doubtless will tend to broaden our 
knowledge of microörganisms and of many important physiological 
questions, 
J. CHRISTIAN Bay. 
The so-called “ Russian Thistle. ”—It is the fate of few 
weeds to reach so suddenly such great notoriety as thet corey ly 
attained by Salsola kali L. var. tragus DC., the so-called “ Russian 
NG ee ee any of the botanical manuals he finds no 
plant under this common name. He will find the “ Common Palt- 
wort.” of the “sandy shore, New England to Georgia ” described in 
such mild terms as to give no idea of the weed as it appears to the 
farmer upon the western plains. 
The species is a native of mountainous regions in both hemispheres. 
