100 SUMMARY OF CURRENT RESEARCHES RELATING TO 



them white and more visible. I then put it on a slide in water to 

 which is added a small drop of Loeffler's raethylen-blue. I watch the 

 staining under the microscope with a low power (I use Zeiss AA, with 

 eye-piece No. 2 or 4). Staining takes place rapidly, and it is much 

 more easy to distinguish the eggs than in an unstained fragment- 

 One can afterwards mount in glycerin or in Apathy's gum-syrup. By 

 this method I have been able to distinguish the sexes in eels 23*5 c.cm. 

 long. I have tried vital staining on elvers. Neutral broth gives very 

 good results, and does not appear to harm them. These stained elvers 

 are very pretty in aquaria." 



Staining Tubercle Bacilli.* — L. Tribondeau adopts the following- 

 procedure : The dried films of sputum are flooded with carbol-fuchsin, 

 and heated to vaporization thrice. The stain is then thrown off and the 

 film treated with nitric acid (acid 1, water 2) until it is yellow. It is- 

 then washed in running water, followed by alcohol (90 to 100 p.c.)^ 

 until the film is of a pink colour. After a rapid wash in tap-water, it is 

 treated with a saturated aqueous solution of picric acid (1 vol. plu& 

 alcohol 90-100 p.c. 1 vol.), or with a solution of methylen-blue 

 (medicinal M.B. gr. 0'50, distilled water 150 c.cm.). These counter- 

 stains are allowed to act for five to ten seconds. The slide is then 

 quickly washed and dried. The picric acid treatment is preferable if 

 tubercle bacilli only are sought for ; the methylen-blue if the cell- 

 elements, etc., are to be shown. 



(5) Mounting', including- Slides, Preservative Fluids, etc- 



Preservation of Fermentation Organisms in Nutrient Media.-f — 

 A. Klocker makes an important communication on this subject. 

 Hansen's conclusion that a 10 p.c. solution of cane-sugar forms an 

 excellent medium is confirmed, but beer-wort is also very good. The 

 Pasteur flask is undoubtedly the best form of vessel for prolonged pre- 

 servation. The present observations were made, dui'ing a period of 

 more than thirty years, on 820 cultures of yeasts and moulds. These 

 included Saccharomycetes, Schizosaccharomycetes, Torulte, Mycoderma, 

 Endomyces, Monilia, Chalara, Oidiwn, and Mucor. For the most part 

 the nutrient medium employed was a 10 p.c. solution of cane-sugar, in 

 which 461 cultures were grown, but 290 cultures were made on beer- 

 wort and 69 on other media. Of the 461 cultures on cane-sugar 

 solution (231 of these being Saccharomyces) 403 survived, whilst 58 

 perished. In the case of the 290 cultures grown on beer-wort (190 

 Saccharomyces) 268 survived and 22 perished. Thus it must be 

 concluded that fermentation organisms can be kept alive for upwards of 

 thirty years. The exceptions to this rule are : — (1) The asporogenic 

 varieties of Saccharomyces ; (2) Saccharomycodes Ludivigii ; (3) Schizo- 

 saccharomyces ; and (4) Aspergillus glauciis. Of the first only 44 p.c. 



• C.R. Soc. Biol. Paris, Ixxx. (1917) pp. 780-2. 



t C.R. des Travaux du Laboratoire de Carlsberg, ii, pt. 6 (1917). See also 

 Nature, Dec. 13 (1917) pp. 289-90. 



