178 NOTES AND MEMORANDA. 



cially if after twenty-four hours it should be slightly warmed, 

 and the cover carefully pressed down with the forceps, and 

 held down with a small weight. The best finish for the 

 edge of the circle he finds to be the same balsam that is 

 used in mounting, laid on with a camel's hair pencil ; since 

 this is neat and handsome, and will not spoil the specimen 

 by running in, as may happen with coloured varnishes. — 

 American Naturalist 



An aid^ Microscopical Drawing. — I wish to call the atten- 

 tion of those interested in microscopical work to a modifica- 

 tion of the existing apparatus used for microscopical drawing. 

 The instrument I use and find more useful than any other 

 for this purpose, on account of its simplicity and the ease 

 with which it is worked, consists of the thinnest possible 

 covering glass placed at a proper angle in front of the eye- 

 piece. The advantage of this thin film of glass over the 

 camera lucida, the neutral tint reflector or the steel disc, is 

 that it enables the pencil to be easily followed in tracing the 

 image Avhich is thrown upon the paper below. An ordinary 

 piece of white glass does not answer the purpose, as it throws 

 two pictures of the object. This doubling of the image is 

 reduced to nothing in proportion to the thinness of the glass. 

 The instrument which I have had made for me by Mr. 

 button, instrument maker, 108, Holloway Road, cost the 

 moderate sum of three shillings and sixpence. It is com- 

 posed of a brass collar (to afiix to the eye-piece of the micro- 

 scope) to which are attached two light brass arms, between 

 which revolves the glass, so that it may be placed at the 

 required angle. — W. Kesteven, Jun. — Lancet. 



Cryptogams in the Interior of Eggs. — Professor Panceri 

 made a communication to the Institut Egyptien at its 

 meeting on December 13th, on the cryptogamic vegetation 

 which he had found within the eg^ of an ostrich. This 

 egg had been given him at Cairo, and was still fresh, the 

 air space having not even been formed. He soon, however, 

 noticed the appearance of dark blotches within the shell, 

 and having broken it open to ascertain the cause, he found 

 that they were produced by the growth of minute fungi. 

 Instances of a similar kind had already been studied by 

 him, and he had communicated the results to the Botanical 

 Congress held at Lugano, in 1859. The believers in the 

 reality of the spontaneous generation of living organisms 

 have not been slow to seize on these cases as an argument in 

 their favour, since a priori it would seem that the shell of an 

 egg would be quite impermeable to germs derived from 

 without. Panceri has succeeded in satisfying himself, how- 



