ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 



651 



12ctm- 



> 7ctm 



15am 



FuUpuncl 



> t7ctm 



deposited on the tray. A glass plate is inserted in the lid for inspecting 

 the distribution of the spray. 



Glass Flask for Preparing Nutrient Media.*— Dr. A. von Borosini 

 describes a glass vessel which obviates the inconvenience of overheating 

 nutrient gelatin. The upper part of 



the flask is funnel-shaped. The illus- F g. 181. 



tration (fig. 181) gives the measure- 

 ments for a two-litre flask. 



Some Laboratory Apparatus.f — 

 Professor S. H. Gage, in order to 

 meet the requirements of a large class, 

 has made use of flat-headed stove 

 bolts as holders for the paraffin blocks 

 to be sectioned by the Minot micro- 

 tome (fig. 182). For small blocks 

 the bolts answer without any modi- 

 fication, but for most objects a larger 

 surface than the head of the bolt is 

 necessary. To increase the surface 

 an American cent, or some coin still 

 larger, is soldered on to the head of 

 the bolt. The convenience of having 

 a sufficient supply of holders for a 

 large class is obvious. The blocks 

 can be kept ready for use in a glass 

 phial ; the fore end should be sealed 

 with paraffin and the holder placed with the block end downwards 

 (fig. 183). 



Another apparatus described is a tray for holding ribands of sec- 

 tions. They are made of wood and measure 30 x 40 cm. The illustration, 

 fig. 184, shows the face and sectional views. The bottom of the tray 

 is covered with paper on which the ribands are deposited; this facilitates 

 the numbering of the sections. The trays may be piled one upon another 

 and so used as covers. 



For the bichromate and sulphuric acid cleaning mixture a low 

 iron kettle lined with heavy sheet lead is recommended, as the lead 

 is not appreciably corroded and the kettle does not burst with the heat. 



New Method for Counting Bacteria.! — Herr A. Klein describes a 

 new method which is specially adapted for counting bacteria in the moist 

 condition. A definite quantity (e.g. 0*5 ccm.) of a liquid culture, or an 

 emulsion of a solid culture in physiological salt solution, is thoroughly 

 mixed with an equal quantity of anilin water-gentian violet. In 2-3 

 minutes the bacteria are deeply stained. The mixture is again stirred 

 so as to distribute the bucteria fairly equally throughout the fluid, and 

 then a standard loopful removed to a clean cover-glass and carefully 

 spread out. When dry the film is mounted in balsam. Fifty fields are 

 then counted, and the number of bacteria in one ccm. of culture or 



* Centralbl. Bakt. u. Par., l te Abt., xxviii. (1900) p. 23 (1 fig.), 

 t Trans. Anier. Mier. Soc, xxi. (1900) pp. 107-9 (3 figs.). 

 \ Centralbl. Bakt. u. Par., l te Abt., xxvii. (1900) pp. 834-5. 



