3$ BOTANICAL MICROTECHNIQUE. 



until the paraffine melts, and then plunged in xylol to dis- 

 solve the paraffine. 



After this the sections, if from objects stained in mass, 

 can be at once enclosed in xylol-Canada balsam. But if 

 they are to be stained, they must first be brought into water 

 or alcohol according to the nature of the stain to be used. 

 Since the separation of the sections from the slide has often 

 occurred during this transfer, I now perform it by carrying 

 the preparations from xylol successively into a mixture of 

 three parts xylol and one part alcohol, 90$ alcohol and 50^ 

 alcohol, leaving them in each fluid two minutes, or as much 

 longer as is necessary. 



I use for this purpose vessels with parallel sides, on the 

 bottom of each of which, at one of the short sides, a piece of 

 cork about I cm. high has been fastened. The slides are 

 then so placed in these that one end rests on the piece of 

 cork and the side bearing the sections is turned downward. 



From 50$ alcohol the preparations can be transferred to 

 water or any suitable staining fluid, without fear of the 

 separation of the sections. At least, I have experienced 

 such a result very rarely even in the use of the most com- 

 plicated staining processes when the above precautions have 

 been observed ; and I have not been troubled by any seri- 

 ous staining of the delicate collodion film by any of the 

 more important methods. 



[50a. Cclloidin sections, when arranged on the slide, may 

 be attached to it by placing the whole in a close chamber 

 over ether. The ether vapor quickly dissolves the celloidin 

 sufficiently to cause the sections to adhere firmly to the 

 slide on removal from the chamber. Should any difficulty 

 be experienced, the sections may be arranged on a thin 

 collodion or celloidin film on the slide and then treated as 

 above. After they are attached, they may be stained and 

 mounted as described for paraffine sections ( 50). Objects 

 stained in mass may be imbedded in cellodin as well as in 

 paraffine. 



For mounting in Canada balsam, celloidin sections may 

 be cleared with a mixture of three parts xylol and one part 



