492 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
return temporarily to an atavistic stage in its evolutionary history. 
With regard to B. diplitherise the author points out that the club-shaped 
expansions of one or both ends are not to be regarded as due to involu- 
tion, for both under natural and artificial conditions where there is 
active growth these expansions will be found, and have moreover a 
striking resemblance to the ends of growing hyphae. Their existence, 
therefore, is only to be explained by their representing a relationship to 
a mycelial fungus. In the case of the tubercle bacilli, preparations 
not unfrequently show threads or filaments composed of unequal 
elements, some of them being conspicuous for knob-shaped expansions, 
similar to those of diphtheria. Such appearances occur not only in 
sputum but in artificial cultivations, e. g. glycerin agar after some weeks 
incubation at 37°. All these preparations behave in the same way 
as B. tuberculosis when treated with appropriate staining reagents ; and 
that they are not involution forms is evident, as the unbranched nature 
of the filaments and the existence of lateral bulgings prove that they 
are in an active condition of growth. 
Bacillar Diseases of Plants.* * * § — MM. E. Prillieux and G. Delacroix 
describe a disease of various cultivated plants produced by a bacillus 
about 1*5 fx long and 0 • 33-0 • 5 /x broad, closely resembling that already 
described as Bacillus caulivorus. It was observed on the potato, Pelar- 
gonium . , Clematis , Begonia , and Gloxinia. Similar, but probably not 
identical, bacilli also attack the vine (the fruit, less often the stem), 
Cyclamen , tobacco, tomato, and Gladiolus ; while apples of various kinds 
are attacked by a Micrococcus. 
Microbes which evolve Hydrogen Sulphide-t — M. N. Zelinsky has 
obtained from ooze in the Black Sea a microbe which he names Bacterium 
hydrosulfureum ponticum, which has the power of evolving hydrogen 
sulphide from the nutritive media in which it is cultivated, and even of 
decomposing inorganic sulphates and sulphites. A microbe with similar 
properties, Vibrio hydrosulfureus , has been obtained from the estuary at 
Odessa. 
Influence of Light on Pyogenic Microbes.! — Dr. P. A. Khmelevsky 
finds that both solar and electric light inhibit the growth of Staphylo- 
coccus pyogenes , Bacillus pyocyaneus, Streptococcus erysipelatis , and 
S. pyogenes ; sunlight destroys their vitality in about six hours, and 
exposure to sunlight seems to mitigate the virulence of the microbes. 
Exposure of agar-agar and jelly to light makes the media less favourable 
for the growth of bacteria. 
Leucocytes and Bactericidal Power.§ — Prof. J. Denys and Dr. J. 
Ilavet find that filtered dog’s blood loses almost entirely its bactericidal 
power; this points to the power lying in the white corpuscles. The 
energetic destruction of microbes effected by “ complete blood ” is the 
result of their ingestion by leucocytes. This is effected in their interior 
* Comptes Rendus, cxviii. (1894) pp. 668-71. Cf. this Journal, 1890, p. 758. 
t Journ. Russ. Chem. Soc., xxv. pp. 298-303. See Journ. Chern. Soc., 1894, 
Abstr., p. 200. 
t St. Petersburg Inaug. Diss., 1893, No. 46, 40 pp. See Brit. Mod. Journ., 
No. 1740 (1894) p. 72. 
§ La Cellule, x. (1894) pp. 7-35. Cf. this Journal, 1893, p. 776. 
