ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 639 



preparations for culture purposes, describes his experiences with pepton, 

 asparagin, somatose, nutrose, and Heyden's medium. To the last are 

 ascribed numerous cultivation virtues, and the following procedure is 

 recommended for making a mixture suitable for most purposes. One 

 gramme of Heyden's medium is stirred up in a little water ; 0*5 grm. 

 salt, 0*1 grm. meat extract, 1*5 grm. agar, and 100 com. distilled water 

 are added. The mixture is well boiled and afterwards steam-filtered. 

 The filtrate is perfectly clear and transparent, but sets somewhat slowly. 

 Slants should be kept in the oblique position for 12—18 hours. 



The foregoing medium seems specially adapted for diphtheria bacilli, 

 and it is not favourable to the growth of Streptococci. 



New Medium for Growth and Differentiation of Bacillus coli 

 communis and B. typhi abdominalis.* — Mr. A. T. MacConkey draws 

 attention to a medium having a marked inhibitory effect on soil and 

 water organisms, and therefore useful for the examination of water, soil, 

 and food-stuffs. It is composed of sodium glycocholate 0*5 per cent. ; 

 pepton 1 • 5 per cent. ; lactose 0- 3-0 '5 per cent.; agar 1*5 per cent.; 

 tap water q. s. The lactose is added after filtration. 



If stab-cultures be made and incubated at 42° C. for 24-48 hours, 

 the tubes containing B. col. com. will be found to have become cloudy, 

 while those inoculated with B. typhi abd. remain quite clear. 



If glucose be used instead of lactose, both tubes become cloudy ; but 

 the cloudiness due to B. coli begins from below, and that from B. typhi 

 from above. In plates made with the glucose medium, incubated at 

 42° C. for 48 hours, and then left at room temperature for 3-4 days 

 exposed to the light, the colonies turn orange-colour. 



Piorkowski's Medium for Diagnosing Typhoid Bacilli.f — Dr. G. 

 Mayer finds that urine is effectively rendered ammoniacal by infecting it 

 with Proteus vulgaris. 5 ccm. of a bouillon culture grown for 24 hours 

 at 22° C. are added to about 2 litres of morning urine. In 15 to 20 

 hours the urine has acquired the correct grade of ammoniacal reaction. 

 This procedure is extremely convenient for Piorkowski's method for de- 

 tecting typhoid bacilli. The medium used is composed of alkaline urine, 

 3*3 per cent, gelatin, and 0*5 per cent, pepton. When cultivated on 

 this urine-gelatin, the typhoid colonies assume characteristic shapes dis- 

 tinguished by root-like ramifications proceeding from a central core of 

 variable dimensions. Forty-five different samples of bacterial growth 

 are depicted. These are subdivided into five groups. The first example 

 resembles a sphere with a few radiating stumpy processes, the last a 

 piece of thistledown. 



Medium for Isolating the Typhoid Bacillus from Stools.:): — Dr. L. 

 Remy used the following medium for isolating the Bacillus typhosus from 

 the stools of typhoid patients : — Distilled water 1000 grm. ; asparagin 

 6 grm.; oxalic acid 0*5 grin. ; lactic acid 0*15 grm.; citric acid 0'15 

 grm.; bisodic phosphate 5 grm. ; magnesium sulphate 2*5 grm.; potas- 

 sium sulphate 1 ' 25 grm. ; sodium chloride 2 grm. All the salts except 

 the magnesium sulphate are pounded up in a mortar, and then placed in a 



* Lancet, 1900, ii. p. 20. 



t Centralbl. Bakt. u. Par., ] te Abt., xxviii. (1900) pp. 125-36 (1 illustration). 



% Ann. Inst. Pasteur, xiv. (1900) pp. 355-70. 



