ZOOLOGY AND BOTANY MICROSCOPY, ETC. 49^ 



capacity to form pigments, can have this function rapidly restored by 

 growing for twenty-four hours on nasgar containing 1 p.c. glucose, and 

 subsequently for twenty-four hours at room temperature. The pigment- 

 producing property thus restored is, however, not transmissible to agar 

 from the cultures on glucose-nasgar. 



Isolation of Bacillus Diphtherias by means of a Simple Medium 

 containing Potassium Tellurate.* — J. F. Smith has found the following 

 medium to give better results in the isolation of Bacillus diphiherm 

 than the original medium of Conradi and Troch : — -sheep serum, 

 sterilized by intermittent heating for one hour at 57° C. 5 c.cm. ; 1 p.c. 

 potassium tellurate solution in distilled water 1*5 c.cm. ; pepton-water 

 agar (neutral to litmus) to 100 c.cm. On this medium B. diphtkerise 

 forms opaque white colonies after twenty hours growth at 37° C. 

 Diphtheroids (Hoffman bacillus, Ozama diphtheroids, etc.) also grow 

 well. Such other organisms as grow, generally show colonies darkened 

 by reduced tellurium. Streptococci form minute discrete colonies and 

 are easily recognized as such. 



Modified Fermentation Tube and a New Medium for Gas- 

 forming Organisms.f — J. W. Hall and F. Nicholls describe a modified 

 fermentation tube for collecting the gas produced by bacteria. It 

 merely consists in ;i funnel-shaped expansion of the lower or open end. 

 They also recommend as a good medium for Bacillus coli neutral veal 

 broth with 2 p.c. silk pepton and 5 p.c. lactose. They note that silk 

 pepton facilitates the growth of colon bacilli in solid media, e.g. agar 



Change of Form of the Tubercle Bacillus when grown on Sperm- 

 oil and G-lycerin-egg Medium.^ — A. H. Miller has found that the 

 tubercle bacillus when cultivated on Dorset's medium (glycerin-egg) to 

 which has been added a little sperm oil (a liquid wax) undergoes certain 

 changes. It becomes plumper, longer, and its ends are pointed. It is 

 beset with large acid-fast granules, the intervening portions being 

 decolorized by the acid. To make the medium the sperm-oil is poured 

 on to the beaten up and filtered egg, and glycerin in normal saline is 

 added to the amount required. The mixture is then well shaken in a 

 flask, poured into sterile test tubes, and set. Coagulation takes place in 

 about three minutes, care being taken not to let the media rupture. It is 

 then sterilized by steaming for about an hour on three successive days. 



(2) Preparing- Objects. 



New Self-regulating Paraffin Bath. § — A very simple form of 

 paraffin bath for embedding tissue for the microtome has been used by 

 C. W. Woodworth in his laboratory for several months, and has proved 



* Journ Path, and Bact., xix. (1914) pp. 122-4. 



t Lancet, 1914, ii. pp. 741-3 (1 fig.). 



I Lancet, 1914, ii. pp. 739-40 (3 figs.). 



S Univ. California Pub. (Zool.) xiii. (1914) pp. 39-42 (2 figs.). 



