202 SUMMARY OF CURRENT RESEARCHES RELATING TO 



Bacillus of Acne.*— II. F. Hartwell and B. C. Sfcreeter find that 

 Bacillus acnes is essentially an anaerobe. Under anaerobic conditions it 

 grows well in all common media, but best on glycerin, agar. Slants 

 inoculated by smearing pus on the surface show fair-sized colonies in 

 from three to five days ; the colonies are raised, greyish white, opaque. 

 The bacillus is Gram-positive, and often has an irregular or beaded 

 appearance ; it is moderately wide ; its length is variable, especially in 

 cultures, where it frequently shows branching forms. It does not form 

 spores. 



(2) [Preparing- Objects. 



Demonstrating the Structure of the Yeast-celLf — H. Wager 

 states that the best fixatives are Gram's iodine solution, Flemming's 

 weak chromic acid solution, and Perenyi's fluid. The best stain is 

 Heidenhain's iron-hsrnatoxylin. The structure of the yeast-cell is best 

 determined by means of sections, and the method is perfectly simple. 

 A quantity of yeast is put into a tube about half an inch in diameter ; 

 it is then fixed and stained, and allowed to settle at the bottom of the 

 tube ; the supernatant liquid is decanted, and is replaced by up-graded 

 alcohols and finally by turpentine or xylol. After a short time the 

 xylol or turpentine is poured off ; soft paraffin wax is added, keeping it 

 melted at as low a temperature as possible until the yeast is impregnated 

 with it. Then wax of a higher temperature is added, and finally the tube 

 is cooled as quickly as possible. It is then broken gently, and the 

 paraffin block with the contained yeast-cells removed. The block is then 

 cut up, and the sections mounted in balsam for microscopical examina- 

 tion. In this way three sections of a single cell may be obtained. 



Investigating Nature of Supposed Algal Coals.J— E. C. Jeffrey 

 worked with material softened by various treatments. In the case of 

 cannel, or cannelard coal, the material was immersed in 70 p.c. alcohol 

 saturated with caustic alkali, and incubated at 60°-70° C. The alkali 

 was then removed by frequent treatment with hot alcohol, after which 

 it was generally found expedient to treat for two or three weeks with 

 strongest hydrofluoric acid. After washing out the acid, the material 

 was embedded in the usual way in celloidin. Sections of about 5 micra 

 thick were made. In the more resistant cannels, especially bogheads 

 and oilshales, it was necessary to treat with aqua regia, and in some cases 

 to replace the hydrochloric by hydrofluoric acid. It was sometimes 

 advantageous to return the material to alkaline alcohol after treatment 

 with acids ; in such cases all the acid must be removed before the pieces 

 are placed in alkaline alcohol, as otherwise they suffer disastrous swelling. 

 After the sections are cut they are dehydrated in a mixture of alcohol 

 and chloroform, in order to avoid softening the celloidin matrix ; after 

 ■clearing in benzol or xylol they are mounted in balsam. In a few 

 instances it was found advantageous to mount in glycerin jelly. In 

 dealing with serial sections, the best procedure is to lay the sections on a 

 slide as they come off the knife, and then dehydrate and clear them in 

 their order. 



* Publications Massachusetts Gen. Hosp., iii. (1910) pp. 200-4(4 figs.). 



t Journ. Inst. Brewing, xvii. (1911) pp. 2-22 (3 figs.). 



X Proc. Amer. Acad. Arts, and Sci., xlvi. (1910) pp. 273-90 (5 pis.). 



