ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 465 



caustic potash until the whole mass is softened. When the mass is 

 washed in water the radula is easily removed. If any dirt bo found 

 adhering to it, the radula should be re-boiled in dilute caustic potash. 

 In dealing with small snails care should be taken, as the organ is very 

 fragile. The preparation may be mounted unstained in glycerin jelly 

 or in isinglass. If it is to be mounted in balsam it must be stained, and 

 picro-carmin is best suited for these objects. Kanvier's and Weigert's 

 formulre are recommended. For the larger kinds of snail the radula 

 should be immersed in the solution undiluted for 2 or 3 hours. For 

 the smaller kinds the solution should be diluted one-half with distilled 

 water, and allowed to act for 3-6 hours. Should the preparation be 

 over-stained, the excess of colour may be removed by means of dilute 

 warm caustic potash. The stained preparations are then treated in the 

 usual way with alcohol, and mounted in xylol-balsam. 



(3) Cutting:, including- Imbedding- -and Microtomes. 



Method of making Sections of Nervous Tissue.* — Dr. S. Tscherni- 

 scheff recommends the following method "j" for making sections of 

 nervous tissue. A piece of spinal cord about 1 cm. thick, fixed by any 

 method, is dehydrated in absolute alcohol for 24 hours, and for another 

 24 hours in anilin. The anilin is removed by immersion in a mixture 

 of alcohol (1) and ether (2). After 24 hours the preparation is trans- 

 ferred to the clove-oil-ether-celloidin solution diluted with an equal 

 bulk of ether. The medium is inspissated to the consistence of sour 

 cream by removing the cover of the vessel. After a few hours the pre- 

 paration is placed in benzol, and finally in 80 to 86 p.c. alcohol, until it 

 has attained the required consistence. 



Instead of celloidin the author tried colloxylin, and found it 

 possessed several advantages over the former. The solution is made as 

 follows : — 10 grm. of dry colloxylin are placed in a mixture of 10 ccm. of 

 oil of cloves, and 50 to 60 ccm. of ethyl-ether. Absolute alcohol is also 

 added drop by drop (but not more than 1 ccm.) to make the colloxylin 

 dissolve quickly. A piece of spinal cord which has been dehydrated in 

 alcohol and anilin is placed in the colloxylin solution freely diluted 

 with ethyl-ether for 24 hours. The cover of the vessel is then removed 

 to allow the solution to thicken. After a few hours the piece is trans- 

 ferred to 85 p.c. alcohol. Colloxylin sections are quite as good as those 

 made by celloidin imbedding. 



Imbedding Bath. J — The Cambridge Scientific Instrument Company 

 make an imbedding bath of new design (fig. 100). It consists of two 

 upper compartments with copper lids, one for specimen jars, small 

 bottles, etc., the other for four large and three small porcelain crucibles 

 with lids, and space for two or three watch-glasses. It has two drying 

 shelves for slides, thermometer, gas regulator, and glass gauge to show 

 the height of water in the bath. The bath is supported on a strongly 

 made iron stand with two gas burners beneath, and is fitted with rubber 

 tubing and Page's glass regulator. It can also be fitted with metal 



* Zeitschr. f. wiss. Mikr., xvii. (1900) pp. 449-51. 



t A modification of Stet'anow'B. Cf. this Journal, 1900, p. 728. 



% List, 1901, p. 12 (1 tig.). 



Aug. 21st, 1901 2 i 



