ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
65 
are mentioned where two quite different microbes combine to produce a 
definite pathological process ; the combined action is far more serious 
than that of either alone. Thus, in a case of meningitis from otitis- 
media, Friedlander’s bacillus and B. pyocyaneus were isolated. Alone, 
it is quite rare for either of these to excite meningitis. Two or several 
microbes do not invade the body simultaneously ; a definite pathological 
condition has already declared itself at the time of the invasion of the 
second. The latter immediately excites its own peculiar action, and does 
this, not by superadding a different pathological condition, but by in- 
tensifying the action of the first. As an example is quoted the case of 
simultaneous bacillar meningitis and croupous pneumonia. All at once 
the symptoms indicated a vertical meningitis as well. The autopsy re- 
vealed the presence of tubercle bacilli at the base of the brain, and 
pneumonia cocci over the vertex. 
Influence of the Induced Current on Bacteria.* — Dr. H. Friedenthal 
reports on some experiments he has made by exposing suspensions of 
M. prodigiosus (5) and of beer yeast (2) to the action of the induced 
current. The electric current had little or no effect. The exposure was 
for about one hour and a half, and the strength varied from 14 to 
"20 amperes. The current was passed along a spiral round the tubes 
filled with the fluid containing the bacteria, a low temperature being 
maintained by a stream of cold water. 
Relation of Immunising Substances to Specific Microbes.f — Dr. E. 
Klein finds that when suspensions of virulent diphtheria bacilli in 
bouillon are injected into the peritoneal sac of guinea-pigs, most of the 
animals remain healthy, the minority dying on the third or fourth 
day. The survivors are eventually able to tolerate a large dose, and 
their blood serum is so strong that 0*25 ccm. is able to neutralise a fatal 
dose administered subcutaneously. It was further found that the sub- 
cutaneous injection of antitoxin had the same effect, and that no morbid 
action occurred from the subcutaneous injection of a fatal dose of a 
gelatin culture previously mixed with 0*1 ccm. of antitoxin. This 
resistance would therefore seem to be due to germicidal substances 
arising directly or indirectly out of the bacteria themselves. 
Gases produced by certain Bacteria.^ — Mr. L. H. Pammel and Miss 
E. Pammel, after discussing the work of previous observers, narrate the 
method of their own procedure, aud give the results of their experi- 
ments with certain gas-forming bacteria. 
Bacillus aromaticus , obtained from rotting cabbage, coagulated milk 
in 48 hours, and produced on potato a yellowish-white growth. Grown 
in pepton-bouillon-glucose and saccharose, there was copious develop- 
ment of gas ; with lactose none. 
Bacillus gasoformans , obtained from water, coagulated milk with 
alkaline reaction, the growth on potato being copious, granular, and 
wrinkled. This bacillus, like the preceding, developed gas copiously 
on pepton-bouillon containing glucose and saccharose, but none with 
lactose. 
Bacillus mesentericus vulgatus coagulates milk with acid reaction, 
* Centralbl. f. Bakteriol. u. Parasitenk., l ta Abt., xx. (1896) pp. 505-8. 
4 Tom. cit., pp. 417-20. % Op. cit., 2 te Abt., ii. (1896) pp. 633-50 (1 pi.). 
1897 F 
