50 



Dissolve the borax in the water, then add the glycerine and mix 

 thoroughly. 



(6.) Carmine, 5 grs. 



Liquor ammoniae fortiss, 20 m. 

 Distilled water. 30 m. 



Dissolve the carmine in the ammonia and water in a test tube, with the 

 aid of heat, and set aide to cool. Then add a to b, mix thoroughly, filter, 

 and preserve in a stoppered bottle. 



I have found that the glycerine being mixed with the borax solution 

 effectually prevents the solution of carmine from changing to the dull lilac 

 colour it assumes when the glycerine is not so employed. The stain, when 

 completed, should be of a pure and brilliant ruby red. 



The method of double staining in these two colours is as follows : — 



1. Soak the sections in distilled water for a few minutes. 



2. Place them in the acid green stain for from 8-5 minutes. They will 

 then be uniformly stained green. 



3. Wash them thoroughly in two changes of distilled water. 



4. Place them in the carmine stain for fire times as long as they were in 

 the green, i.e., for from 15-25 minutes, stirring them about in the stain with 

 a camel's-hair brush from time to time. 



5. Wash them very thoroughly in two changes of methylated spirit, 

 allowing them to remain in it for at least 15 minutes. 



6. Float them in oil of cloves, and as soon as they sink to the bottom of 

 their own accord they are ready for mounting in balsam, the whole process, 

 at the outside, taking no more than an hour for its completion. 



The sections can be preserved for some time in the oil of cloves if they are 

 kept carefully in the dark, but it is best to mount them as soon after stain- 

 ing as possible. 



It will be observed that by this method, although the bast and wood are 

 very perfectly differentiated from the cellular tissue, they are not differen- 

 tiated at all from each other. I would suggest that the differentiation of 

 the fibres from the vessels may prove a profitable direction in which to 

 experiment. 



In order to cut really good sections, three things are absolutely 

 necessary : — 



1st. The object must be properly prepared. 



2nd. It must be properly imbedded ; and 



3rd. It must be properly cut. 



I am afraid people generally look upon the first as a rather superfluous 

 proceeding. Animal tissues, of course, require very careful preparation, 

 but vegetable stems or leaves are looked upon as quite ready to be cut just 

 as they are taken from the plant. Never was there a greater mistake ; 

 woody stems are generally much too hard to be cut without previous 

 softening, whilst leaves, petioles, peduncles, and tubers are generally far too 

 soft. 



The plan I would suggest is this : — 



1st. If the object is too large to be cut whole, divide it into pieces of a 



