BOTANICAL GAZETTE. 2g 



as you did the carrot. Then, third: — There is a section holder which 

 is to be used only with the paraffine. It is an e egant, somewhat 

 costly instrument, with I think on the whole a more limited range of 

 usefulness than the second form I have described. But whether you 

 take the second or the third form be sure that it his a glass top for 

 the cutting surface. Brass does well for a time, but sooner or later 

 bceomes rough and so blunts the edge of the cutter, which can never 

 be too sharp. 



Now as to the act of cutting: some objects may be cut dry, others 

 may be required to be moistened with water or even with alcohol, and 

 a little of the same fluid may be allowed a ong the knife edge to se- 

 cure a good or uninjured specimen. The value of a section does not 

 (beyond certain common sense limits) depend on its sixe. A small, 

 thin section may, nay will, reveal more structure than a large one 

 thick enough to be nearly opaque. Hence, make your object as large 

 as you can to make it thin, bur no larger. 



Suppose it is made, and made properly, worthy of mounting per- 

 manently. How shall we do this? First, remove all dirt by washing 

 in clean water, then remove all air by immersing in water, or glycerine 

 or alcohol, depending upon what you mean to do with it next, and also 

 in which we shall distend or shrink the object least. Remember here 

 the stages 1 gave in my previous paper concerning tbe repeated alco- 

 hol baths it must liave before it comes to be rendered clean in oil of 

 cloves. This rids you of all water and makes it as transparent as it 

 can be made. Now if the object has had the preliminary stages in 

 alcohol and oil, its suitable and final mount should be balsam. I have 

 cast aside all balsam with benzols and balsam with chloroform an J 

 come down to the slower evaporations — what is called balsam pure. 

 Some objects are not injuriously distorted by this process. Indeed 

 some delicate spores even stand it well. But this is not the rule. 

 Spores do not generally tolerate it and retain their original symmetry 

 and size. Hence we must find some other process. 



Take for exan.ple a section of Solorina saccala — a lichen with 

 charmingly large and handsome spores. I would rid it of air by first 

 putting it in water, then after an hour or two, into glycerine, where if. 

 may remain twelve or more hours. And then I mount it in Farrants 

 medium (bear in mind Farrants, not Tarrants medium) which Dr. 

 Carpenter says is made by "dissolving four parts (by weight) of pick- 

 ed gum arabic in four parts of cold distilled water, and then adding 

 two parts of glycerine." Make without heat, stir but don't shake it, 

 and when it is made, strain it through washed cambric, put it into a 

 bottle along with a small lump of camphor which will prevent fungi 

 from developing in the sweet solution. Now, shall you make a cell 

 or not, for your object? Not unless that object is thicker than (for a 

 simple standard) a sheet . of writing paper. If however the glass 

 cover cannot be made to remain flat on the slide, or if an appreciable 

 distance exists between the slide and the cover, then you need a cell. 

 What it shall be made of depends upon i's re(iuired thickness. If a 

 deep cell is needed then you must go back to the rubber, block tin, 

 or other cells such as I have already named. If however you want 



