94 GENERAL BIOLOGY. 



chloral-hydrate iodine. Watch a few min- 

 utes for the effect. 



KAEYOKINESIS. 



1. The tip of a young onion-root.* 



Find and sketch seven or eight stages. 



2. The testis of the lobster.f 

 Find the principal stages. 



Sketch. 



* Method of preparation : Cut off a quarter of an inch of the tip 

 of young roots of an onion growing in water in a hyacinth- 

 glass ; put them into Hermann's fluid in the dark for 48 hours ; 

 wash in running water 24 hours ; imbed in paraffine and stain on 

 the slide with Haidenhain's iron-hsematoxylin, leaving the sec- 

 tions in the haematoxylin solution overnight. 



f Pieces of the testis a quarter of an inch long should be pre- 

 served and stained as the onion-root. In making the sections the 

 pieces of testis should be cut lengthwise. 



