108 KANSAS UNIVERSITY SCIENCE BULLETIN. 



objects have shifted somewhat in position. They can be ad- 

 justed by simply pushing the cover slip toward one or the 

 other side. In this way the finest adjustments in position can 

 be made. Objects can be brought from a very decided in- 

 clination to an upright position. 



Preparations of tadpoles made in this manner are especially 

 instructive in sowing the ventricles of the brain, the eye, the 

 developing semi-circular canals of the ear, and the different 

 portions of the alimentary tract. It is, of course, possible to 

 make any desired dissections of embryos, and to mount them 

 in this fashion. I found that preparations of the pronephros, 

 mesonephros, and developing gonads can be handled very 

 nicely in this manner. This use of hard balsam for mount- 

 ing is not radically new, but is capable of much wider use 

 than has ever been made of it. 



