
Sag The American Naturalist. [September, 
months, then washed quickly and placed in alcohol of 50 per cent. two 
to three days, which should be renewed a few times. They are then 
transferred to 95 per cent. alcohol, and left until they show plainly a 
greenish color (two to four weeks or more), 
The preparations are then ready for sectioning, and may be cut 
without imbedding, or after imbedding in celloidin. Two methods of 
ease are used : 
. The section is placed in a one per cent. solution of gold ehtoadés 
to heli two per cent. hydrochloric acid has been added (about two 
hours), then washed in distilled water, and transferred to a ten per 
cent. solution of potash for half a minute. 
The section is then washed in distilled water, and there left until the 
following reducing fluid (to be made fresh each time) is prepared : 
Acid. sulfurosum . E A AE E A  Oee 
Tinct. iodi., 3 per cent. (kid Ge wre et g OS Grops, 
Mix, and add 
Ligo fetrichlord: o reos as ei, os 1 drop: 
This fluid must be made very exactly and quickly, and the moment 
it is ready the section is placed in it and left until it assumes a rose 
color. If left only a few seconds too long it becomes dark red, and is 
worthless. : 
As soon as the proper color appears the section is transferred to 
distilled water, and then to absolute alcohol ontheslide. After ten to 
fifteen minutes it may be cleared in clove oil and mounted in balsam. 
The slide is to be kept in the dark. 
2. The section is placed for two hours in the following solution : 
Gold chloride, 1 per c co rg OE 
Ammonium van nadia; aa solution . . to drops. 
Mid DYGROCM OR oii soe o 6 ss oa fe g reps. 
Wash, and transfer to the following (freshly prepared) mixture for % 
to 1 minute : 
Caustic potash, 10 = aa pee E a 
Ammonium vanadicum . . Seo A UME 
Permanganate of anah. 10 per cent. . a w tO dróps 
Wash, and expose to the following reducing fluid, freshly prepared : 
Tin eo og oe ee Pree ee 
Aq. des 
Tron se tio on. neers cs 
Acid. sulfarosanii be a ee 
gap! tt “s/s atop. 
i i ngee 


