278 Modern Microscopy 



formed a few evolutions, one end would not readily be 

 known from the other. Subsequently, hot water is care- 

 fully conducted to the bottom of the dish in which the 

 ribbon floats, by means of a pipette. Take care not to 

 introduce air -bubbles through squeezing the teat too 

 vigorously. Upon application of hot water the sections 

 will open out in a wonderful manner, and ribbons appar- 

 ently crumpled beyond hope may be restored by this simple 

 means.* The amount of hot water that the floating sections 

 will bear may readily be seen by the paraffin gradually 

 losing its white opacity as its melting-point is approached. 

 Filtered distilled water should be used. 



Mounting Ribbon Sections. — Having the stretched 

 ribbon floating upon the water, take the properly-prepared 

 slide (remembering as to the sequence of sections) and, 

 placing it under the ribbon, float the ribbon into position 

 upon it. It is sufficient to place one side of the slide in the 

 water under the ribbon, which may then be held in position 

 with a brush whilst the whole is lifted out of the water. 

 Any required number of strips of ribbon may be placed side 

 by side to fill up the slip, after which all of the superfluous 

 water possible should be removed from the slide, and it 

 should then be placed in the rack sections downwards to 

 dry at room temperature, or stand the rack upon the top of 

 the paraffin oven. On no account should any further 

 progress be attempted until the sections are thoroughly 

 dry. They will keep indefinitely if dry and free from dust. 

 Manipulation of the ribbon is easily done by means of a 

 crow-quill sable hair-brush, and a wide, thin and fiat bone 

 chemical scoop. 



In pushing the sections from the bone scoop on to the 

 surface of the water for stretching, care must be taken 

 not to introduce water between the ribbon and the 

 bone, or failure will result from the sections sticking to 

 the instrument. These manipulations are easily and 



* Do not rely upon this method for making good the results of bad 

 knife sharpening. 



