1580 



Journal of Applied Microscopy 



\V 



number of organisms may be concentrated in the same cell. The cell may 

 also be filled by means of the yarn siphon, a single strand being sufficient for 

 the passage of many Infusoria. Such preparations may be kept for a long time 

 by placing the cells in a larger vessel containing water, so that the upper open 

 end of the U is above the level of the water, while a part of the U is immersed 

 in it. 



A Circulation may be kept up in the U 

 cell as shown in Fig. 2. The cells are placed in 

 a cylindrical dish with their inner and upper ends 

 resting against a smaller cylindrical vessel set in 

 the center of the first. The water is supplied to 

 the cells from the central vessel (the edge of 

 which should be but 5 mm. above the open end 

 of the U's) by yarn siphons (S"). The fluid is 

 removed from the outer vessel by means of a 

 constant level siphon (S'). The inner vessel is 

 supplied with water from an elevated bottle 

 closed with a two-hole stopper. Through one 

 of these holes passes the siphon, which dips 

 below the level of the water in the inner vessel. 



Through the other 

 the air-tube is in- 

 serted. This passes 

 nearly to the bottom 

 of the bottle, and by 

 means of raising and 

 lowering it the water 

 in the inner cylin- 

 drical vessel may be kept at any desired height. In siphoning, woolen yarn pro- 

 duces a more rapid flow than cotton. 



Absorbent Cotton may be conveniently used for making temporary or per- 

 manent microscopical'preparations. A very small amount of dry absorbent cotton 

 is spread upon the slide, a few drops of fluid with the Infusoria are added, and 

 the cover-glass lowered horizontally so that the animals shall be caught in the 

 meshes of the cotton, and not above or below the fibers. The cover-glass is 

 then secured with rubber bands, and the preparation treated in any desired way, 

 subjected to the action of killing, dehydrating agents, etc., without any fear of 

 the Infusoria being washed away or misplaced. F. W. Bancroft. 



Fig. 2. 



Looss, A. Zur Sammel- und Conservierungs- Directions are given by this eminent 



technik von Helminthen. Zool. Anz. 24: i i • ^.u \ •„<- t^ t-u^ ^^u^^t-:^^ „„ i 



^„ ^^. .^^ -,,« T^^T helminthologist for the collection and 



302-304, 309-3 I C>, I9OI. o 



preservation of parasitic worms by 

 methods which prevent undue contraction and distortion, and which are at the 

 same time available for field work or in the absence of laboratory facilities. 



lYcmatodes. — The strongly contractile forms are not readily killed in extended 

 state except by the old method of washing in normal salt solution, stretching 



