194 SUMMARY OF CURRENT RESEARCHES >TING TO 
Bacterial Disease of Sweet-corn.* — Mr. F. C. Stewart finds, on 
sweet-corn in Long Island, a disease different from that already known 
on Indian corn produced by a bacillus. It is caused by a bacterium 
(unnamed) with the following characters : — Cells short, motile, with 
rounded ends, occurring commonly in pairs; each pair about 2 *5-3 *3 
X 0*65-0 *85 fx; no spores were found. 
Spore-formation and Germination as Diagnostic Criteria of Spe- 
cies, j — Herr G. Burchhard, in a contribution to the morphology and deve- 
lopment of bacteria, compares the spore-formation and germination of a 
large number of species, and comes to the following important conclu- 
sions : — (1) Spore-germination for each species of bacterium is charac- 
teristic and invariable. (2) Hence spore-germination is the safest 
diagnostic criterion for the recognition of a species. (3) In addition to 
polar and equatorial germination, there is also an oblique one ( B . lox- 
osus). (4) There are bacteria with regular bipolar germination (B. hi- 
polaris). (5) There is a polar germination with equatorial rupture of 
the spore-membrane (B. idosus). (6) There are bacteria which possess 
two spore-membranes (Bad. Belroselini). (7) In many species the 
position of the spore is, within certain limits, a variable one (Bad. 
perittomaticum , Bad. brachysporum , Bad. JHamentosum, Bad. paucicutis. 
Bad. Armoracise). (8) In rare cases the spores are of unequal length 
( B . gomosporus). (9) The shape and size of the spore is dependent on 
the nature of the nutrient medium and the age of the culture. (10) The 
spore does not alway lie in the long axis of the bacterium (B. loxosus). 
(11) As the spore ripens, the mother-cell may undergo a complete change 
of shape (Bad. angulare). 
Thermophilous Bacteria. | — Herr A. Schillinger instituted some 
experiments on the fermentive power of thermophilous bacteria, by in- 
oculating sterile milk with earth and incubating at 66° C. The milk 
coagulated in 24 hours, and in 24 hours more there was copious gas 
formation, which lasted for 5-6 days. In grape and milk-sugar bouillon 
impregnated with earth, there arose copious gas formation at 66° after 
24 hours, but in unsaccharated bouillon only a scanty production. Four 
species of thermophilous bacteria were isolated from different samples 
of earth ; three of these coagulated and fermented milk at 37°, while 
the fourth acted on grape and milk-sugar, and on starch. These charac- 
teristics were, however, not verified at 66°. The designation of thermo- 
tolerant in lieu of thermophilous is suggested for these bacteria, in view 
of the fact that 66° is not proved to be the optimum. 
Acetifying Bacteria.§ — M. D. P. Hoyer, in a lengthy article, dis- 
cusses many of the characteristics of acetic acid bacteria. The study is 
divided into four parts. In the first are described the species and varie- 
ties of acetic acid bacteria, while the remaining three aro devoted to 
respiration and nutrition, zymotic nutriment, and oxidation of various 
substances. For the details the original should be consulted. The 
* Bull. Soc. New York Agric. Exp. Stat., 1897, pp. 423-39 (4 pis.). See Bot. 
Centralbl., lxxvi. (1898) p. 316. 
t Klein and Migula, Arb. a. d. Bacteriol. Inst, zu Karlsruhe, ii. pp. 1-64 (2 pis.). 
See Beibl. z. Hedwigia, xxxvii. (1898) pp. (213)-(214). 
X Hygien. Rundschau, 1898, p. 568. See Centralbl. Bakt. u. Par., 2 te Abt., iv. 
(1898) pp. 925-6. § Arch. Neerland. Sci. exact, et nat., ii. (1899) pp. 190-240. 
