534 SUMMARY OF CUKREXT RESEARCHES RELATING TO 



the cholera organism whilst inhibiting that of extraneous organisms. 

 Dieudonne's blood-alkali-agar, the first of these, was found to be not 

 strictly selective, permitting the growth of other types of vibrio, of 

 B. pyocyaneus, and some other organisms. Moreover, it was not ready 

 for use until 18 hours after the plates were poured. Pilon's blood- 

 soda-agar is ready for use at once, is of no less selective value than 

 Dieudonne's medium, but its usefulness is greatly diminished by the 

 fact that it does not favour the growth of cholera vibrios in first culture 

 from the tissues. 



T. Kabeshima's hsemoglobin-extract-soda-agar here described pos- 

 sesses the advantages of being ready for use the moment its preparation 

 is complete, and of being strongly selective for the causal agent of 

 cholera. The method of preparation is as follows. 10 c.cm. of 18 p.c. 

 soda are heated with 80 c.cm. of melted 3 p.c. nutrient agar for 10 

 minutes. This is cooled to 50° C, and a solution of 3 grm. Pfeiffer's 

 haemoglobin extract in 10 c.cm. normal saline is added. After thorough 

 mixing, the liquid is poured into seven Petri dishes. These are left 

 uncovered until the agar has set, and are then put into an incubator to 

 dry off the condensation water. 



(2; Preparing- Objects. 



New Method of Blood Fixation.* — H. G. Phmmer gives the follow- 

 ing procedure for fixing blood films. 



1. Vapour Method. — Expose the film whilst wet to the vapour of a 

 solution of iodine in chloroform for 10 to 15 seconds, until it is dis- 

 tinctly yellowish. When the temperature is low the vessel should be 

 warmed in order to get the vapour given off freely. Place the film, 

 when it has become surface-dry, in chloroform, or in alcohol and ether, 

 equal parts, for 2 hours. This removes the iodine, and the film may be 

 stained. The author uses : — A. Giemsa. Three to eight drops are 

 placed on the film, and immediately after double the number of drops 

 of distilled water ; leave for 2 to 12 hours. Wash with tap-water. 

 Drop on two to eight drops of orange-tannin solution, and leave for 

 15 seconds. Wash in tap- water up to 2 minutes. Dry with filter paper. 

 Mount in cedar-oil or liquid parafiin. 



B. Carbol-fuchsin for from 2 to 12 hours. Wash in tap- water. 

 Remove excess of stain with alcohol. Differentiate in oil-of -cloves 

 saturated with orange Gr. Wash in xylol, and mount in cedar-oil or 

 liquid paraffin. 



C. Iron-h^ematoxylin or Kernschwarz for 24 hours. 



2. Solution Method. — Make a saturated solution of potassium iodide 

 in * 8 p.c saline, and add iodine to saturation. Mix five to six drops of 

 this with 10 c.cm. of salt solution. Mix in a marked pipette equal parts 

 of this and the blood to be examined. (In the case of organs, small 

 pieces may be crushed in an equivalent quantity of the iodine solution 

 to form an emulsion.) Take large drops and make a thickish film. 

 Wait until the surface has begun to dry, and place in alcohol-ether for 

 2 hours. Then proceed as in the vapour method. 



* Proc. Roy. Soc, Ser. B, Ixxxvi. (1913) pp. 289-91. 



