MICHIGAN ACADEMY OF SCIENCE. 95 



A CONVENIENT METHOD OF WASHING FIXED PREPARA- 

 TIONS. 



BY RICHARD DE ZEEUW. 



It is comparatively easy to wash a limited amount of material 

 after fixation, but when it comes to taking care of the washing of 

 material for a large class in technique, cytology or embryology, 

 the instructor in charge is faced by a rather annoying problem. 

 The objection to all the schemes suggested is in the fact that the 

 sink, which above all else should be kept free, is all cluttered up. 



The writer lias constructed a bit of apparatus, which has given 

 very satisfactory service for two years. It has appealed to all who 

 have seen it as answering the purpose admirably. That is the ex- 

 cuse for the present note. 



The apparatus (Fig. 14) consists of a galvanized iron box (A), 

 which may be made of any required dimensions. There is a pipe 

 (B) to enable one to have a constant stream of water running in 

 the trough, which has an overflow pipe (C) at the opposite end. 

 The material to be washed is put in Gooch Crucibles. A piece of 

 cheese-cloth is put over the opening, and a rubber band is snapped 

 around it to keep the cheese-cloth in position. The whole is then 

 immersed in water bottom side up. The bottom of the crucible is 

 perforated with small holes. The air is thus allowed to escape and 

 the water to enter the crucible. Care should be taken not to im- 

 merse it so far as to cause the water to close up the openings. This 

 will keep that air in, when the crucible drops to the bottom of the 

 trough on being released the air is out. If not, take it out, blow 

 in the holes to free them of water and try again. 



The crucibles may have a thread run through one of the holes 

 and a tag fastened to the other end, which hangs on the outside of 

 the trough. This enables any one to remove any particular speci- 

 men from the wash-trough Avithout disturbing am^ of the others. 



Since there is a continual current of water in the trough, it has 

 been found advantageous to place the crucibles on their sides with 

 the ends directed toward the ends of the trough. Thus the cur- 

 rent will pass in at the cheese-cloth covered end and out at the 

 perforated end ensuring perfect removal of the fixing agent. And, 



