ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 



173 



Schizophyta. 



Schizomycetes. 



Bacteriotoxic Action of Water.* — R. Greig-Srnith has conducted 

 a series of experiments with regard to the bacteriotoxic action of water 

 on Bacillus prodigiosus and B. typhosus, and has come to the conclusion 

 that ordinary tap-water contains substances of the nature of bacterio- 

 toxins, the toxicity of which is increased by boiling. It is suggested 

 that these toxins are of similar nature to those demonstrated in soils, 

 from which they may be extracted by rain and thus find their way into 

 natural water supplies. The following protocol to one of his experi- 

 ments shows the order of reaction that he has obtained : — 



In order to exclude the possibility of the reduction of numbers being 

 due to the transference of the bacilli from a saline to a non-saline 

 medium, the bacteria were grown in sodium-chloride-free nutrient agar 

 for several generations, and the experiment repeated. A similar reduc- 

 tion in the number of the bacteria was observed, thus showing that the 

 reason for the destruction of the organisms is not to be found in the 

 lessened salt content of the media. 



Destruction of Paraffin by Bacillus prodigiosus and Soil- 

 organisms, t — R. Greig-Smith has demonstrated the fact that B.prodigi- 

 osus and soil-organisms generally, are capable of utilizing hydro-carbons. 

 His first experiments were conducted by saturating sifted dried blood 

 with paraffin, removing the excess of paraffin, and mixing thoroughly ; 

 portions being then incorporated with sand and moistened with a suspen- 

 sion of B. prodigiosus. After fermentation for ten days, the loss of paraffin, 

 as determined by extraction, was about 5 p.c. In another series of 

 experiments in which casein and kieselguhr were used instead of blood 

 and sand, the loss of paraffin ranged from 10 to 22 p.c. The bulky 

 nitrogenous matter was then dispensed with. Kieselguhr was treated 

 with paraffin, ground and sifted, mixed with sand and calcium carbonate, 

 and sterilized. A synthetic medium containing peptone or asparagin 

 was then added, and the medium inoculated with 2 c.cm. of a suspension 

 of B. prodigiosus or soil-organisms. After incubation for a month at 

 28° C, the loss of paraffin occasioned by B. prodigiosus was 11 p.c, and 

 49 p.c. by the soil-organisms. 



* Proc. Linn. Soc, New South Wales, iii. (1914) pp. 533-7. 

 t Proc. Linn. Soc., New South Wales, iii. (1914) pp. 538-41. 



