PREPARATION OF MICROSCOPICAL MOUNTS OF VEGETABLE TEXTILE 



FIBERS. 



By Romyn Hitchcock. 



The method of mounting vegetable textile libers here described has 

 been adopted in the National Museum with perfect success. The per- 

 manent preparations leave nothing to be desired, for they clearly reveal 

 the minute structure of the fibers, and their appearance does not change 

 with time. Possibly the coarser fibers, after a few months, become 

 rather more transparent than at first, but this change is so slight that 

 it is of no consequence. Moreover, the process is simple, rapid and sure, 

 even in the hands of a novice. In evidence of this statement it may be 

 said, that Mr. H. English, a young man who had never made a micro- 

 scopical mount before, in the summer of 1884 made one hundred and 

 seventeen preparations of fibres in fluid mounts, from printed instruc- 

 tions, precisely as described below, having seen the operations performed 

 two or three times by an experienced mounter, yet not one of his prep- 

 arations has shown an imperfection up to the present time.* 



The method is as follows : The fibers are cleaned, disintegrated, and 

 prepared precisely as for microscopical investigation, the object being 

 to make the mounted specimens resemble in every respect the freshly 

 prepared fibers. The specimens for mounting are selected to show the 

 variations in the size of the fibers, and the form of their ends. They 

 are then placed in the mounting medium. This may be water without 

 any addition, which is the medium most generally appropriate, or a 

 mixture of water and glycerine in equal parts, which is to be recom- 

 mended for the coarser and more opaque varieties. 



The glass slips are prepared in advance by running upon them a thin 

 ring of clear shellac in alcohol just large enough to receive the cover- 

 glass. This is done on a turn-table, in the usual way. When this ring 

 is thoroughly dry the mounting may be proceeded with. First put the 

 slide again on the turn-table and run a fresh coat of shellac over the 

 ring. Then, immediately or after a couple of minutes, put a large drop 

 of the mounting fluid into the cell, transfer to it the specimen selected 



*A11 of Mr. English's preparations are still perfect in 1889'; five years after they 

 were made. 



II. Mis 170, pt. 2 42 637 



