ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 229 



case to consist of agglutinated masses and of shining motionless bodies, 

 which when transferred to fresh media initiated vigorous growth of 

 typical vibrios. On the other hand, the toxin of one water vibrio was 

 incapable of agglutinating cultures of the other. 



Gram-staining Bacteria in the Intestines of Infants.* — Dr. Calm, 

 following on the lines of Tissier, isolated ix number of organisms from 

 the evacuations of breast-fed and hand-fed (cow's milk) infants, and 

 studied such as were not decolorised when stained by Gram's method. 

 The B. anaerobicus was not met with in the course of these experiments, 

 but the acidophilus was invariably present (post-mortem) in the organs 

 of infants which were the subjects of intestinal catarrh, &c. An ex- 

 tremely sketchy description of some of the cultural characteristics of 

 B. bifidus, acidophilus, and aerobius ramificaius is included in the com- 

 munication. 



Enumeration of Water Bacteria.| — As the result of a series of 

 experiments to confirm or disprove the statement made by Abba at the 

 Congress on Hygiene at Como, Walbaum lays down the following data. 



In bacteriological examinations of water for the purpose of deter- 

 mining the number of organisms present, the examination should be 

 carried out by means of plate cultivations on nutrient agar, and only in 

 special cases should gelatin be resorted to, e.g. only when it is necessary 

 to identify the organisms. The plates should be kept at a constant 

 temperature of 20° C, and the result expressed as the number of 

 bacteria per cubic centimetre after 14 days' incubation. 



The reasons which led him to formulate these conclusions were that 

 in the first place gelatin liquefies so rapidly as to be useless after a few 

 days' incubation, while parallel experiments with agar plates proved 

 that it possessed no advantage over the agar in point of number of 

 colonies developing after incubation. Secondly, that only in a few 

 cases were any colonies visible after 24 hours' incubation ; usually from 

 the second to the third day's incubation the number of colonies re- 

 mained stationary, but showed a definite increase from the fourth up to 

 about the eighth day, after which no alteration in numbers took place. 

 The daily increase in the number of colonies was so irregular that it 

 was impossible to utilise or even accept Abba's statement that " at the 

 end of three days 30 p.c. of the bacteria present in a sample of water 

 have developed colonies." 



Experiments with Deycke's Media.:}:— Dr. Bruno Bosse grew fresh 

 virulent strains of the Vibrio cholerse, V. Kochi, Bacillus diphtherise, 

 B. typhi abdominalis, B. coli communis, B. pyocyaneus, streptococci, staphy- 

 lococci, &c, upon the various Deycke's media and compared his results 

 with those obtained from control plate and streak cultivations upon 

 ordinary agar and gelatin. He found that nutrient medium retarded 

 the growth of all except the two vibrios ; whilst the colour production 

 of the B. pyocyaneus was markedly affected. 



Nutrient medium I. favoured the growth of the colon, typhoid, and 

 diphtheria bacilli, also the cholera vibrio. 



Nutrient medium Ila forms a good selective medium for the Klebs- 



• CeDtralbl. Bakt., 1" Alt., xxx. (1901) pp. 721-6. 



t Tom. cit, pp. 790-8. % Tom. cit, pp. 798-804. 



