768 



SCIENCE 



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



be published in a teehnieal bulletin of the New 

 York Experiment Station. 



Field Organisation and Laboratory Technique, Ca- 

 nadian Section — International Joint Commission 

 Pollution Investigation, 1913: F. A. Dalltn. 

 Period of investigation — April 10 to October 



10, 1913. 



Field laboratory located at nine (9) bases, from 



Fort Frances, Ont., to Kingston, Ont. 

 Equipment at each base comprised: 



2 incubators —18° C, —22° C. and 37° C, de- 

 signed to hold maximum number of samples. 

 2 sterilizers, one for glassware and the No. 3 



BramhaU Deane Autoclave. 

 400-500 petri dishes with copper cases, 4 copper 

 25 c.c. pipette cases containing 30 pipettes each, 

 3 copper 1 c.c. pipette cases containing 60 

 pipettes each, 300-400 6-oz. glass stoppered 

 sample collection bottles. 

 Apparatus for obtaining deep samples. 

 Several hundred Dumas bulbs, necessary table 



apparatus and media-making equipment. 

 Twelve thousand eight hundred (12,800) samples 

 were collected and examined. The determination 

 of the total bacteria count on nutrient agar 

 (+10) at 18° -22° C. (48 hours), the count at 

 37° C. (24 hours), and the quantitative estima- 

 tion of B. eoli as indicated by fermentation in lac- 

 tose bile at 37° C. (48 hours), not less than four 

 (4) dilutions used for the latter — usually 1, 5, 25, 

 50 c.c. were tubed (1/1000, 1/100, 1/10) only 

 when required. Sample collection points were lo- 

 cated on straight lines by a time interval method 

 (cheeked by different landmarks, buoys and light- 

 houses). Stoppers and necks of sample bottles 

 protected from contamination by a rubber dam 

 held by a band. The dam was dipped in mercuric 

 chloride solution before being re-used. 



Each field laboratory examined on an average of 

 52 samples per day. Max. amount 103 samples per 

 day for 3 days in succession. Ten (10) to twenty 

 (20) daily samples taken at each sample collection 

 point. Special paragraphs on tabulation, account- 

 ing system, plating and tubing technique, handling 

 of media, media reaction and washing of glass- 

 ware. 



The Virulence of the Resistant Minority: Frank 



SCHOFIBLD. 



The work described has been done in an en- 

 deavor to obtain facts which would give a satis- 

 factory basis for answering the following ques- 

 tions: Considering bacteria of the same species, 

 have those which exhibit the greatest resistance to 

 germicidal action a corresponding increase of 

 pathogenic power over their fellows which succumb? 



Or, are the few which survive exposure for long 

 periods to detrimental conditions practically 

 innocuous? 



In the experiments done swabs were inoculated 

 from pure culture of B. Diphtheria and placed in 

 the sunlight and others in the dark. At the same 

 time definite quantities of special broth were in- 

 oculated, incubated for two days and varying 

 amounts injected into guinea-pigs of known 

 weight. Cultures were made from the inoculated 

 swabs at different periods such as 30 days and 

 number of colonies developing noted, for instance 

 100, then again at 35 days when number of col- 

 onies might be 50. By careful manipulation the 

 time when but two or three organisms capable of 

 growing on the culture media were left could be 

 estimated. Such colonies would represent the 

 most resistant of the strain used. From such col- 

 onies broth was inoculated and incubated under 

 similar conditions, as at the beginning of experi- 

 ment. Guinea-pig inoculation was made and re- 

 sults compared with results recorded at commence- 

 ment of experiment. A series of eleven experi- 

 ments such as these were undertaken and the re- 

 sults warranted the following conclusion : That 

 cultures made from the most resistant individuals 

 of a strain usually exhibited pathogenic proper- 

 ties similar to the less resistant organisms of same 

 strain, the virulence neither being increased nor 

 decreased materially. 

 The Influence of the Hypochlorite Treatment of 



Water upon the Development of Algce : Carrie 



M. Derick. 



Professor Derick briefly reported some general 

 observations incidentally made by a graduate stu- 

 dent, Miss Clare Miller (Mrs. Wasteneys), in the 

 course of a study of the Algal Flora of the Island 

 of Montreal, in 1911 and 1912. Collections of 

 algae made in October and November, 1911, were 

 maintained in sixty or more aquaria in the bo- 

 tanical laboratories of McGill University. In addi- 

 tion to series in various media, parallel cultures 

 were grown in ordinary tap water. At that time, 

 the city water was being regularly treated with 

 hypochlorite of lime, less than one part to a mil- 

 lion parts of water being used. The development 

 of deleterious bacteria being thus prevented, the 

 cultures of alg£e in this water, which contained all 

 the necessary mineral nutrients, were unusually 

 vigorous and long-lived. At temperatures about 

 20° C, blue-green algae, especially Oscillatoria 

 tenuis Ag., 0. splendida Grev. and Bivularia 

 liwnuitites Ag., flourished. Anabcena, on the con- 

 trary, usually died or passed into a resting condi- 



