115 



Notes on Microscopic Technique. 



M. S. Markle, Earlham College. 



During the past few years I have been using very successfully a 

 method of staining a number of slides at one time, a description of whicll 

 may be of interest to others who have occasion to prepare large numbers 

 of slides for class use or for research. The principal features of the 

 method were suggested to me by Miss Louise Sawyer of the Department 

 of Biology of Beloit College. 



As shown in the illustration, the slides are held between the soils of 

 a brass spring about an inch in diameter, made of No. 13 wire and wound 

 with the coils in contact. By holding the spring in the left hand and 

 forcing the first two coils apart with the thumb nail, the first slide may 

 be inserted. After this, pressure applied by the thumb upon the slide 

 just inserted separated the coils for the reception of the next slide. 



As staining jars, I am now using Bausch and Lomb preservation 

 jars No. 15166 holding 600 c.c, but Stender dishes about 100 mm. deep 

 might prove to be more satisfactory. Vessels to contain stains in which 

 the slides rest for a time (such as safrannin) are more economical of 

 stain if larger. 



A coil long enough to hold 12 to 15 slides has been found to be 

 most satisfactory. The spring is kept uppermost until the final xylol is 

 reached, when the spring is reversed, allowing the slides to be pulled out 

 one at a time for mounting. It is easy to hold the rest of the slides with 

 one hand while removing a slide with the other. 



The spring I am using was made by Orr and Lockitt, Chicago; a 

 spring about 18 inches long cost 65 cents at that time. Any hardware 

 dealer ought to be able to obtain such a spring. 



I have found it desirable to use 3 jars of 95 per cent, alcohol as well 

 as 3 jars of xylol in the series of reagents through which the slides are 

 run. As the alcohol becomes loaded with stain or water, the lowest 

 grade is discarded, each of the others is reduced one grade and the 

 third jar refilled with pure alcohol. The same scheme is used for xylol. 

 By this means, one always has one vessel of pure reagent. Economy of 

 reagents and efficiency of work are facilitated. 



