130 THE AMERICAN MONTHLY [Apr 



Observations Upon Spindle-Formation in Anthers. — 

 Mr. A. A. Lawson at the University of California has re- 

 cently spent some time upon this subject using- the anthers 

 of Cobaea scandens on account of their large size, large 

 mother-cells and large nuclei. 



The anthers were gathered and immediately fixed in the 

 field. The following fixing* fluids were used : 



Alcohol, 95 per cent. 



Chromic acid, 1 per cent. 



Flemming's mixture, chromic-osmic-acetic, strong so- 

 lution. 



Wilson's sublimate-acetic. 



Boveri's picro-acetic. 



Corrosive sublimate, saturated solution in 95 per 

 cent alcohol. 

 The best results were obtained by using Flemming's 

 strong solution diluted with one volume of water. The 

 material was washed in running water from six to eight 

 hours. It was then carried through different grades of 

 alcohol by means of an apparatus consisting of a tumbler 

 with a cover and a glass funnel. The funnel was of such 

 a size as to be supported in the mouth of the tumbler. A 

 piece of parchment paper was folded and placed in the fun- 

 nel in the same manner as for filtering. Ten per cent solu- 

 tion of alcohol was placed in the tumbler and the anthers 

 were placed in water in the funnel. The mouth of the tum- 

 bler was covered and the material was thus allowed to re- 

 main for an hour or two. The alcohol in the tumbler was 

 changed at intervals to 25 per cent, 50 per cent and 95 per 

 cent solutions. By this means the effect of the rapid 

 change from a weak to a strong solution of alcohol was ob- 

 viated. The anthers were then thoroughly dehydrated in 

 absolute alcohol. They were then placed in a mixture of 

 bergamot oil and alcohol and then in pure bergamot oil. 

 From the bergamot oil they were transferred to a mixture 

 of bergamot oil and paraffin, and from this to pure paraffin, 

 where they remained at a temperature of 55 deg. C. for 

 twenty-four hours. Microtome sections of 2 s microns in 

 thickness were used. 



