230 The American Naturalist. | March, 
in the sugar vats. Transitions to the nude form were also observed 
in old sugar cultures, which had become acid from the growth of the 
organism. Moreover, the tough, shiny, elastic cartilaginous form de- 
veloped on sugar media during the first week or two of growth was 
always observed to break down later on, becoming first flabby and 
then juicy soft. The nude form cannot be distinguished from Strepto- 
coccus; and both Migula and Lehmann and Neumann now write 
Streptococcus mesenteroides. Steamed potato proved excellent for 
the cultivation of the nude form. The cartilaginous form grew 
well on carrot. The organism is able to ferment the following car- 
bohydrates with the formation of an acid: grape sugar, cane sugar, 
milk sugar, maltose, and dextrin. Glycerin is not fermented. It 
can produce its enormously thick envelope only from grape sugar 
or cane sugar after it has inverted it. The sheath is composed of 
a gum-like substance called dextran by Scheibler. It is incorrect to 
speak of a “dextran fermentation.” There is no such thing. The 
sugars are fermented with production of an acid, but the dextran 
is as much a product of growth as cellulose. The acid formed from 
the grape and cane sugar (and presumably from the lactose and 
maltose) is lactic. This was identified by its calcium salt and zine salt. 
Under ordinary conditions no appreciable gas was formed from any of 
these carbohydrates; but in the presence of calcium chlorid, or in the 
absence of oxygen, bubbles were given off (apparently CO,). Calcium 
chlorid when added in 3-5 per cent. portions to properly prepared 
nutrient sugar solutions greatly favors the formation of dextran. 
Growth in such cases was very rapid, 101.5 grams of the Leuconostoc 
in one instance being developed out of 50 grams of cane sugar in four 
days. The organism is aerobic and also facultative anaerobic. It can 
invert cane sugar, but produces no peptonizing or diastatie ferments, 
and has no effect on cellulose. It is able to take both its N. and C. 
from peptone or from asparagin, but not from ammonium tartrate. In 
a 5 per cent. cane sugar solution containing the requisite inorganic salts 
no growth was obtained on adding ammonium tartrate, ammonium 
nitrate, or potassium nitrate, which would tend to show that it cannot 
take N. from these salts. The thermal relations are peculiar. Although 
a great variety of cultures in all stages of growth were examined for 
spores, nothing of the sort was found, and it is believed that no spores 
exist, certainly none of the sort described by van Tieghem. The 
organism is nevertheless very resistent to heat, even in the nude form. 
It grows at 9° to 11° C., but forms no acid. At 14° to 15° there 18 
plain growth in 4 to 5 days with production of acid. “Grows well at 
