766 



SCIENCE 



[N. S. Vol. XXXIX. No. 1012 



When neutralized another wash bottle with an ali- 

 quot portion of acid is substituted. A final de- 

 termination of the amount of ammonia in the soil 

 flask plus that of the acid in the wash bottle shows 

 the exact amount of ammonia given off. A large 

 series of flasks and wash bottles may be served by 

 the same filter pump, using appropriate connec- 

 tions of Y and T tubes with heavy-walled rubber 

 tubing. It is necessary to use screw pinch cocks 

 throughout the system in order to regiilate the flow 

 of air through the wash bottles and to see that none 

 are cut off. Such a system should be used and ad- 

 justed for at least twenty-four hours before the 

 soil and material to be ammonified are added in 

 order to make sure that all is in perfect working 

 condition. 

 A Bacterial Disease of the Larvae of the June 



Beetle, La-chnosterna Spp.: Zae Nobthrup. 



During the summer of 1912, the larvae of the 

 June beetle, La-chnosterna spp. committed serious 

 depredations to crops. Specimens sent in to the 

 entomological department by the farmers were 

 found to be diseased and were turned over to the 

 bacteriological laboratory for the determination of 

 the etiology of the infection, and, if practicable, 

 to use the living parasite as a remedial measure. 



This disease which is characterized by a blacken- 

 ing of the affected parts, was found to be due to a 

 micrococcus, which was found microscopically in 

 smears and in sections from diseased tissue. This 

 organism was isolated from the affected tissues of 

 a living grub and liquid cultures were used for the 

 inoculation of the soU in which healthy larvsB 

 were then placed. Oftentimes infection occurred 

 within a short time ; the most marked infection oc- 

 curred when an incision was made in the integu- 

 ment, a characteristic lesion developing within 

 twenty-four hours. It was discovered that an ex- 

 cessive amount of water in such inoculated soil 

 favored the rapid progress of the disease. This 

 seems to be one of the most important factors in 

 determining the fatality of the infection. This 

 disease may be transmitted characteristically to 

 larvae of the southern United States June beetle, 

 Allorhiiia niticla and to the American cockroach, 

 Periplaneta americana, but is non-pathogenic to 

 rabbits or guinea-pigs. The black pigment char- 

 acterizing the disease is probably produced di- 

 rectly or indirectly by the activity of the bacterial 

 cells within the larval tissues; the cocci and the 

 integument cells in which they are imbedded do 

 not take the ordinary or the Gram stain but re- 

 main dark brown in color. From the character- 

 istic lesions produced by this organism it has been 



named "Micrococcus nigrofaciens." No results 

 have as yet been obtained in trying out this organ- 

 ism as a remedial measure for the destruction of 

 the white grub. Cultures of the micrococcus have 

 been sent to Porto Eico for this purpose. 



WEDNESDAY, DECEMBER 31, 1913, TWO-THIRTT 

 'CLOCK 



Sanitary Bacteriology 

 A Numerical Comparison of the Organisms Pro- 

 ducing Gas in Lactose Bile Isolated from the 

 Baltimore City Water Supplies: J. Bosley 

 Thomas and Edgar A. Sandman. 

 The water supply of Baltimore city is derived 

 from two streams which flow through a rather 

 populous rural district. The larger stream, which 

 has an average daily flow of about one hundred 

 million gallons, drains a watershed supporting 

 many large dairy farms, while the other, with a 

 flow of twenty million gallons per day, is derived 

 from a watershed supporting fewer dairy farms 

 in proportion to its area, but known to be subject 

 to a greater extent to possible sewage pollution. 

 It, therefore, occurred to us that there might be 

 shown in one of these supplies the presence of a 

 different relative proportion of certain types of 

 organisms than in the other supply; and a pollu- 

 tion derived largely from dairy-farms and creamer- 

 ies is obviously of a less serious character than a 

 pollution caused principally by the introduction of 

 sewage. For the classification of these organisms 

 four sugars, in addition to the customary use of 

 gelatin, were used, viz.: lactose, dulcite, saccha- 

 rose and dextrose. Endo's agar was used for iso- 

 lating the organisms in pure culture, and the re- 

 sults of a study of the character of colonies 

 formed on this medium is given in the original 

 paper. The average number per c.c. of the sev- 

 eral types of organisms was estimated by consid- 

 ering the number of positive and negative tests in 

 each dilution and following the method described 

 by Phelps before the American Public Health As- 

 sociation in 1907. The results of this work, em- 

 bracing 383 isolations from untreated water, show 

 an average number of 2.79 organisms per c.c. giv- 

 ing cultural characteristics of B. coli communis 

 and B. coli communoir, and 9.31 organisms per 

 c.c. giving cultural characteristics of B. {lactis) 

 aerogenes and B. acidi laotici, in the Gunpowder 

 River, which is exposed to pollution from dairy- 

 farms, in comparison with 5.12 organisms of the 

 former types and 4.98 of the latter types in the 

 Jones Fall supply, which is more exposed to sew- 



