106 NOTES AND MEMORANDA. 



given it a third coating in the same manner, he gave it a final coat of 

 gold size, and he had never had any trouble with cells closed in this 

 manner. He believed that the secret of success in a great measure 

 was owing to the washing ; the gold size was also removed from 

 contact with the glycerine by the elastic varnish under it. Glycerine 

 would do no harm to gold size when it could not get at it. Subse- 

 quently, at the Secretary's request, Mr. Hislop said that his experience 

 was that of Mr. Suffolk, for he had found no difficulty in keeping in 

 glycerine. His plan was to make a good seat for the cover, first by 

 a thick rinfT of gum dammar, allow this to become sticky, and then 

 put in the glycerine, lay on the cover, and then carefully wash oif 

 all superfluous glycerine. When perfectly washed and dried, put on 

 two or three coats of gum dammar to finish it. He had in this way 

 mounted slides which had kept well for more than two years, and he 

 strongly recommended gum dammar for the purpose. Care must be 

 taken that the glass was perfectly clean, and if this were attended to, 

 and a good bed was made of cement on which to place the cover, there 

 would be no doubt as to the result. He had some large preparations 



. such as a whole frog or toad passing from the tadpole condition — 



which had been put up in this way, and they were perfectly intact, 

 and not the slightest exudation had ever been observed. Finally, Dr. 

 Matthews mentioned that it was from Mr. Hislop that he derived the 

 idea of making a ring upon the slide ; in doing this it was necessary to 

 wait before putting on the cover until the gum dammar became " tacky," 

 because if this were not done it would be found that tears of dammar 

 would nm in and spoil at least the appearance of the slide around the 

 edge. If, after making the ring, the slide were put aside for an hour 

 before proceeding to mount, there would be no danger of this occur- 

 rence. 



A New Sub-stage for a 4-inch Objective. — At the meeting of the 

 Quekett Club on May 26th, Mr. James Smith exhibited a simple con- 

 trivance designed to obviate a difiiculty frequently met with in using 

 Ross's 4-inch objective, in consequence of the great length of focus 

 required. It consisted of a small mahogany sub-stage, attached to the 

 wooden stand of the microscope, and jointed so that it could be set at 

 any angle required to make it parallel with the ordinary stage when 

 the body of the instrument was inclined. The object to be examined 

 was placed upon the sub-stage, and viewed through the orifice in the 

 upper stage, by which means an ample length of focus and a great 

 degree of steadiness were obtained. For the illumination of opaque 

 objects in this position, the concave mirror was admirably adapted, 

 and the lamp did not in that case require to be placed so near to the 

 instrument as to cause any inconvenient amount of heat to the observer. 

 The habits of living insects could be most advantageously studied by 

 this arrangement; and he had recently observed, when examining a 

 spider, that, in attacking a fly, and enveloping it in a quantity of web 

 previously to finishing his meal, a silken thread was spun from each of 

 the five spinnarets, instead of from one only, as under ordinary circum- 

 stances. 



