2<)0 SUMMARY OF CURRENT RESEARCHES RELATING TO 



the passage from the bacterial to the cellular grade was perhaps the 

 most important advance in the evolution of living beings, as the cellular 

 type was the starting point for the evolution, not only of the Protozoa, 

 but through them of the whole visible everyday world of animals and 

 plants, in all of which the cell is the unit of structure. Further, with 

 the cellular type were initiated, in the President's opinion, two of the 

 most universal and characteristic peculiarities of living beings, namely, 

 the phenomena of sex and the tendency to form species. 



B. Technique.* 

 (1) Collectinj Objects, including Culture Processes. 



Selective Action of Dieudonne's Medium.f — E. Glaser and Y. Hachla 

 have carried out an investigation upon Dieudonne's alkaline blood-agar 

 medium, devised for the isolation of cholera vibrios, with a view to 

 ascertaining whether the growth of certain organisms other than cholera 

 was permitted. They found that Bacillus faecal is alkaligenes, an organism 

 often present in normal faeces, grew on this medium as luxuriantly as 

 Vibrio cholerse, and suggested that a ready means is thus afforded for 

 the separation of B. typhosus and B.fsecalis alkaligenes. B.fluorescens 

 and B. fluoresceins non liquefaciens both grow well upon this medium at 

 22° C, but show little growth at 37° C. Proteus vulgaris grows well at 

 both room temperature and blood heat, but Proteus piscicidas versicolor, 

 while showing good growth at room temperature, is restrained at a 

 temperature of 37° C. 



New Method for Studying Movements of Bacteria.:}: — M. Liacho- 

 wetzky gives the following account of his method : Melted agar is poured 

 into a small Petri dish, which must be perfectly horizontal. Upon the 

 surface of the solidified agar is laid a sterile Swedish filter-paper, marked 

 with three intersecting millimetre scales. The paper is moistened by 

 the condensation-water of the medium. Should this prove insufficient, 

 a small quantity of saline may be added. By means of a special 

 platinum needle, the paper and agar are inoculated, from a culture of the 

 organism to be investigated, at the point of intersection of the milli- 

 metre scales. Small pieces of sterile silk, from 2-5 mm. in length, are 

 placed in various positions upon the scales. The plate is then placed in 

 the incubator, the horizontal position being exactly maintained. After 

 a suitable time, according to the nature of the investigation, and of the 

 organism that is being studied, these silk threads are transferred to 

 broth tubes, which are then incubated for one to three days. If the 

 organisms, starting from the point of intersection, travel far enough to 

 reach one of these threads, they will infect it, so that subsequent cultiva- 

 tion from this thread will yield a growth of the organism. Thus, if the 

 broth tubes, inoculated with the nearer threads, give a growth, while 



* This division 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 Centralbl. Bakt., lte Abt., Orig., lvii. (1911) pp. 371-84. 



$ Tcm. cit., pp. 180-91. 



