1582 Journal of Applied Microscopy 



best killing fluid for nematodes intended for collections and systematic work was 

 determined after much experiment to be 70 per cent, alcohol heated to 80-90°C. 

 With few exceptions the worms thus killed are well extended, free from wrink- 

 ling, and give excellent histological detail, tissues being much less brittle than 

 when killed in acids or metallic salts. For subsequent examination the worms 

 are transferred to a mixture of glycerin and alcohol, from' which the latter is 

 evaporated over a warming oven at 50-G0°C. until the pure glycerin alone 

 remains. For some worms, such as Scierostoma, the mixture may contain as 

 much as 20 per cent, glycerin, for more delicate species it must not exceed 2-3 

 per cent, before evaporation. The evaporation of the alcohol must be very slow 

 in the case of those forms with thick cuticula. Permanent mounts of small 

 species may be made in glycerin jelly. Specimens from the concentrated 

 glycerin may be transferred to 96 per cent, alcohol directly, without shrinkage, 

 for subsequent sectioning. All attempts to bring nematodes from formalin into 

 alcohol without collapse failed utterly. 



Acanthocephali. — Shaking in normal salt solution, followed by similar treat- 

 ment in sublimate, leaves the specimen fully extended with proboscis protruded. 



C. A. K. 



Marpmann. G. Eine neue Vorschrift zum The author recommends the following 



Konservireren von Zoologischen mid Anat- ° 



omischen Praparaten. Zeitsch. f. angew. fluids for use in fixing and preserving 



Mik. 7: 14, 1901. zoological specimens and anatomical 



material where it is necessary or desirable that alcohol should be avoided. The 



following formula is given for the fixing fluid : 



Sodium fluoride, - - - 50 gm. 



Formaldehyde (40 per cent.), - 20 c. c. 



Water, 1000 c. c. 



From this fluid the preparations are passed into the following mixture for 

 preservation : 



Glycerin (28 °B) - - . - 500 c. c. 



Water, ----- 1000 c. c. 



Magnesium chloride, - - - 100 gm. 



Sodium fluoride, - - - 20 gm. 



This fluid is said to have preserved the natural colors of anatomical material 



and of reptiles. Objects for sections should be washed three or four times in 



water, and then treated to the usual grades of alcohol. Glycerin material may, 



however, be passed directly to the embedding soap. c. a. k. 



