Production of Sections 277 



few minutes in the midst of cutting, it will sometimes 

 happen, owing to effects of expansion and contraction, that 

 upon resuming the cutting the first section will be thicker 

 or thinner, or perhaps even missed altogether. 



In the process of cutting, the sections will probably 

 become slightly crumpled or compressed together longi- 

 tudinally, so that previous to fixing upon the glass slips 

 they should be stretched in the manner to be described 

 immediately. For the preservation of the correct sequence, 

 the calculated number of slides should be prepared by 

 having the designation of the organ written with a diamond 

 upon one end of the slip, together with the number of the 

 slip, and indicating the direction in which the consecutive 

 sections run by an arrow . This enables the side on which the 

 sections lie to be at once distinguished. As a support for the 

 slips, the sloping water-colour palettes will be found useful. 



Mayer's Albumen. — Each slide then receives a small drop 

 of Mayer's albumen ; this is rubbed over the surface of the 

 slide with a clean finger, and finally almost cleaned away 

 with another finger, leaving a scarcely visible film. Mayer's 

 albumen is made as follows : 



White of a perfectly new-laid egg ... 25 c.c. 

 Pure glycerine ... ... ... 25 ,, 



Sodium salicylate ... ... 0*5 gramme. 



Place in a perfectly clean bottle, and allow to stand for a 

 week or more, with an occasional vigorous shaking, until 

 the soda is dissolved. Subsequently, filter into a clean and 

 dry bottle. It will take a week or more to filter, and must 

 be protected from dust meanwhile ; the solution will then 

 keep indefinitely : its use is to stick the sections to the slide. 



Stretching Ribbon Sections. — To stretch the sections 

 take a strip of ribbon sufficient for one length — say, six 

 sections — and float them upon warm water contained in a 

 long and narrow glass dish, about 3 inches by 1 inch, 

 remembering at which end the first section occurs. This 

 also will prevent the ribbon turning about upon the 

 surface of the water, in which case, after it had per- 



