ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 307 



advantage. It is important to sow the medium with large drops of the 

 suspected pus. Lastly they rind that gonococcus is easily cultivable 

 anaerobieally on their medium. They do this either by covering the 

 surface of the infected film with a layer of oil, or by cultivating in 

 vacuo. 



Collecting Eeiworms.* — M. V. Lebour and T. H. Taylor, after 

 alluding to the damage done to rhubarb by Tylenchus devastatrix, and 

 to the ordinary methods of obtaining eeiworms for examination, de- 

 scribe a procedure for cleansing the raw material. It is based on the 

 habit that eeiworms have of climbing up capillary films. For this 

 purpose silk threads are employed, to each of which is suspended a blob 

 of cotton wool. The cotton wool serves as a receptacle for holding 

 the crude material obtained from the rhubarb. The upper ends of the 

 threads are attached to a glass ring, which is supported upon the sloping 

 sides of a funnel-shaped vessel containing water, this shape being chosen 



Fig. 33. 



in order that the blobs may hang clear (fig. 33). As the threads become 

 saturated the eeiworms ascend along the silk strands and, passing over 

 the brim into the water, congregate on the floor of the vessel. 



Casein as a Cultivation Medium.f — G. Seliber has used for 

 studying certain organisms a medium in which casein is the basis. The 

 formula given is as follows :— K 2 HP0 4 , 1 grm. ; MgS0 4 , 0'3 grin.; 

 NaCl, O'l grm. ; CaCl 3 , 0*1 grm. ; distilled water, 1 litre. In certain 

 cases it is useful to add to the foregoing a few drops of Fe 2 Cl 6 . The 

 solution, to which 1 p.c. pepton may be "added, is neutralized and then 

 alkalinized with slight excess of NaHO. To the alkalinized medium is 

 added 0'5 p.c. casein. The medium is heated over a water bath and 

 shaken up in order that the ingredients may be disseminated throughout. 

 When ready the solution is sterilized for fifteen minutes at 115° C, and 

 then filtered. To the filtrate is added 1 p.c. sugar, and finally auto- 

 claved previously to being distributed in test-tubes. 



* Nature, May 7, 1914, p. 242. 



t C.R. Sec. Biol. Paris, lxxvi. (1914) pp. G39-41. 



