ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 425 



The results found by direct counting are more accurate than those 

 obtained by plating, but, as shovai by the table, they are not directly 

 comparable with them. These total counts are in no sense intended to 

 supersede the specific cultural and other tests for B. coli or other 

 individual groups of organisms. 



B. Technique.* 

 (1) Collecting- Objects, including- Culture Processes. 



Culture Medium for Rapidly Detecting the Presence of Bacilli 

 of the Typhoid Group. f — C. Botelho has devised a medium the 

 principal ingredient of which is the " cotton-blue Poirier Cj B." This 

 is dissolved in lactophenol Amann (lactic acid 1, pure carbolic acid 

 crystal 1, glycerin 2, distilled water 1), and diluted with a third of 

 distilled water. 2. White sugar 200 gnu., completely dissolved in 

 100 grm. water, o. 2 p.c. sohition of NaHO. 4. Agar 15, pepton- 

 Chapoleaut 10, salt 5, water 1,000 grm. SteriUze after complete 

 solution. 



The medium is made as follows : — In a flask put 100 grm. of the 

 agar, liquefy and add 2 c.cm. of the cotton-blue solution, and 10 c.cm. 

 of the sugar solution, boil, and then add 7 c.cm. of the caustic soda to 

 2 per 100. Boil again till the agar is completely decolorized and after- 

 wards distribute into tubes. 



Tubes inoculated with bacilli of the typhoid group become blue in 

 four or five hours, while the coli group tubes remain uncoloured. 



(2) Preparing- Objects. 



The Examination of Dysenteric Stools for Amoebse Cysts. :j: — 

 J. Carles and E. Barthelemy describe the following method of searching 

 for amoebae cysts in stools from dysenteric patients. After mixing the 

 stool thoroughly, 20 grm. are placed in a glass of 125 c.cm. capacity. 

 Add, while stirring, a sufficient quantity of dikiting fluid to obtain a 

 homogeneous emulsion (the diluting fluid consists of salt solution and 

 10 p.c. formalin). Pass the emulsion through a silk sieve of 1)0 meshes 

 to the centimetre, of which the interstices are of an average of GO fj, 

 (when searching for helminth ova employ a sieve of 32 meshes to the 

 centimetre with interstices of 225^). The liquid obtained after filtering 

 is distributed in tubes and centrifuged for one minute at a speed of 

 1,800 revolutions per minute. Keject the supernatant fluid and dilute 

 the residue with the following liquid: — Citric acid 12 grm., water 

 80 grm., formalin 2 grm. Add 1 or 2 c.cm. of sulphuric ether and 

 shake strongly to detach the, residue. Centrifuge for thirty seconds at 



* This subdivision contains (1) Collecting Objects, including Culture Pro- 

 cesses ; (2) Preparing Objects ; (3) Cutting, including Embedding and Microtomes ; 

 (4) Staining and Injecting ; (5) Mounting, including slides, preservative fluids, etc.; 

 (6) Miscellaneous. 



t C.R. Soc. Biol. Paris, Ixxx. (1917) pp. 435-7. 



; C.R. Soc. Biol. Paris, Ixxx. (1917) pp. 402-3. 



Au(j. loth, 1917 2 F 



