186 SUMMARY OF CUBRENT RESEARCHES RELATING TO 



filtrate is then centrifuged and water is added till the specific gravitj is 

 reduced bo 1060. After repeated centrifugalization, the sediment is 

 washed several times with salt solution, shaken up with 20 p.c. antiformin 

 solution and again centrifuged and washed. The precipitate is then 

 mixed with 10 can. water containing five to ten drops of hydrochloric 

 acid, centrifuged and again washed. On microscopical examination of 

 the resulting precipitate, numerous cysts can now be found, which may 

 he stained readily with neutral red solution. 



Simple Cultural Method of Distinguishing Diphtheria from 

 Pseudo-diphtheria Bacilli.* — (i. Schmidt has reviewed a paper by 

 M. af Heurlin, which appeared recently in the Munch. Med. Wochenschr., 

 in which the author has employed a new medium for the differential 

 cultivation of diphtheria and pseudo-diphtheria bacilli. This medium 

 consists of a 1 p.c. agar medium with a 1'5 glucose content, and an 

 addition of 100 c.cm. normal sodium carbonate solution to each litre. 

 Fifty-three strains of true diphtheria were employed, and after fifteen 

 to forty-eight hours, anaerophil or true anaerobic colonies developed. 

 On the other hand, with most strains of pseudo-diphtheria the growth 

 was unequivocally aerobic ; principally on the surface of the medium, or 

 as little points up to 8 mm. below the surface. The remainder of the 

 pseudo-diphtheria strains employed did not produce any growth on this 

 medium. 



New Medium for the Cultivation of Chick Tissues in Vitro. t 

 H. F. Smyth has devised a method of growing chick tissues in vitro, in 

 which the use of chicken plasma is done away with and an agar medium 

 substituted therefore. After trying various combinations of egg albumen 

 and agar, it was found that the following preparation gave the best 

 results. Egg albumen was removed to a sterile Erlenmeyer flask, to which 

 was added an equal amount of trypsinized pepton solution, prepared by 

 dissolving 10 c.cm. Witte's pepton and 0'5 c.cm. trypsin in 200 c.cm. 

 of Ringer's solution, and digesting for three hours at 40° C. The 

 solution was then made up to 1 litre with Ringer's solution, boiled for 

 twenty minutes, filtered and sterilized. A second solution (clarified 

 with egg-white and stored in. small flasks) was made by dissolving 

 15 grrn. of agar in one litre of Ringer's solution. The mixture, when 

 combined, was in the following proportions : egg albumen 25, trypsinized 

 pepton 0*25, agar 0*75, and Ringer's solution 74. It gives a soft 

 agar, rich in egg albumen, reinforced by partially digested pepton. It 

 is easy to prepare, is very efficacious, does not solidify if kept above 

 42° C, and the contained albumen will not coagulate if kept below 60° < '. 



Preparation of Haematin.:}: — J. A. Menzies describes the following 

 method of preparing haematin, which appears to be an improvement on 

 the potassium carbonate method usually employed. 



Add to blood one-fourth of its volume of syrupy solution of potassium 

 carbonate, place in a porcelain capsule and heat on a water bath till it 



* Centralbl. Bakt. Ref., lxii. (1914) pp. 389-90. 

 t Journ. Med. Research, xxxi. (1914) pp. 255-9. 

 X Proc. Phys. Soc., xlix. (1914) pp. iv-v. 



