ipo 



CALIFORNIA ACADEMY OF SCIENCES. [Proc. :,n Ser. 



They were then placed in the inner part of a dehydrator^ and 

 barely covered with water. The outer part of the dehydrator 

 was filled with 95 per cent, alcohol. After remaining in the 

 dehydrator for twenty-four hours, the material was removed 

 to 95 per cent, alcohol and left for six hours. It was then 

 run up successively through a mixture of equal parts of 95 

 per cent, of alcohol and absolute alcohol, absolute alcohol, 

 a mixture of equal parts of absolute alcohol and bergamot 

 oil, bergamot oil, a mixture of equal parts of bergamot oil 

 and paraffin (43°), and a mixture of paraffin (43^) and 

 paraffin (52°). The anthers remained six hours in each. 

 When in bergamot oil they were placed on the paraffin 

 oven. Paraffin (52°) was used for imbedding and the 

 microtome sections were cut from 3 to 5 microns in thick- 

 ness. The sections were fixed to the slide either with albu- 

 men (the sections being first spread out on a layer of 

 water over the albumen, after which the slides were 

 placed upon the paraffin oven to dry) or with 80 per cent, 

 alcohol according to Eisen's method (Eisen 1897). The 

 latter method is preferable as the sections may be stained 

 almost immediately. After mounting, the sections were 

 stained with the Flemming triple stain. They were first 

 placed in safranin, where they remained twenty-four hours. 

 On removal they were decolorized with 95 per cent, alco- 

 hol until the stain was removed from everything except 

 the nucleolus. They were then washed with water and 

 placed in gentian violet, where they were allowed to 

 remain from five to fifteen minutes. There was then 

 poured over the slide in rapid succession, a concentrated 

 solution of orange G, 95 per cent, alcohol, and absolute 

 alcohol. Clove oil was then poured upon the slide and the 

 progress of decolorization watched under the microscope. 



1 The dehydrator was made in accordance with the suggestion of Prof. W. A. Setchell, 

 as follows: A funnel of appropriate size is deprived of its neck and supported in the 

 mouth of a tumbler or beaker. A piece of parchment paper folded in the same manner 

 as for filtering is placed in the funnel. A cover fits over the top of the tumbler to pre- 

 vent evaporation. Alcohol is placed in the tumbler; the material is placed in the funnel 

 and covered with water. The rapidity of dehydration depends upon the quantity of 

 water, the strength of the alcohol, and the thickness of the parchment paper, and can be 

 kept under perfect control. 



