96 BOTANICAL GAZETTE [FEBRUARY 
hours, the material was washed for a few hours, and then 
carried through several grades of alcohol to 70 percent. It was 
necessary to decolorize with peroxide of hydrogen, and this can 
be done advantageously by mixing it with alcohol to a strength 
of 70 per cent. alcohol. 
After dehydration with absolute alcohol, cedar oil has been 
used as an infiltrating agent. A small quantity is poured into 
the absolute alcohol, and into this the material soon sinks. 
When clear, a change to pure cedar oil is made for a number of 
hours, then into a mixture of paraffin and cedar oil, and finally 
into pure paraffin for a few hours. A change of the pure paraf- 
fin is well, in order to rid the tissues of all cedar oil; for a 
trace of the latter may cause electrification and crushing in sec- 
tion cutting. 
Staining. —A modification of Flemming’s triple stain of 
safranin, gentian violet, and orange was relied upon primarily, 
but quite generally supplemented with iron haematoxylin and 
orange. In using the triple stain, various safranins were used; 
but with Symplocarpus a final effect of the safranin was of no 
value, and it was quite generally discarded for a double stain of; 
gentian violet and orange. Ehrlich’s gentian violet was used, 
and for some stages short staining with the strong solution 
would suffice; but in cases where there was difficulty in staining 
the spindle fibers, or cytoplasmic radiations, it was found much 
better to stain from eighteen to twenty-four hours ina tumbler 
of water containing about one cubic centimeter of the gentian. 
The orange was used from a fraction of a minute with spindle 
stages to several minutes with mature pollen grains. After the 
orange, I have found it advisable to wash out most of the surplus 
gentian in absolute alcohol, or rinsing at first with 95 per cent. 
alcohol, if desired. Differentiation with clove oil was effected 
by simply dashing the slide with the oil, since a much longer 
action often causes a loss of detail. The sections are then fixed 
and cleaned in bergamot oil before mounting. In some cases 
it is well to dash with bergamot oil before differentiating the 
orange with clove oil, especially in stages where the gentian is ) 
