ZOOLOGY AND BOTANY, MICROSCOPY, EIO. 359 



snipped off by a pair of scissors, to a drop of water on a slide, cover, 

 and examine vriih. a power of four hundred or so times. The tempera- 

 ture of a comfortable room is about right ; with less heat the move- 

 ment is very slow. Success is more certain if the bulb has started to 

 grow, as they often do in a cellar. Care should be taken in removing 

 the membrane, for the cell- walls are very delicate, and easily wrinkle, 

 forming unsightly and annoying irregular lines, over what should be 

 the clear open cell. 



The material commends itself for its accessibility at any time, and 

 especially in winter when other things may not be readily obtained, 

 and for the extreme ease of preparation. 



Examining Embryo - growth in Birds' Eggs.* — Dr. L. Gerlach 

 describes a successful method which he has devised for watching the 

 embryo-growth in birds' eggs through a small glass " window " made 

 at the smaller end. After detaching the end with a bent pair of 

 scissors, a little albumen is taken out, so that the germinal disc of the 

 yolk turns upwards ; the liquid is then put back. Gum-arabic solution 

 is spread on the opening, and wadding put round it, then a small 

 watch-glass is fixed on it with gum ; collodion and amber-lac being 

 afterwards added. The eggs must lie horizontally in the incubator ; 

 development then goes on normally, and may be observed till the 

 fifth day (thus comprising the time most interesting to the embryolo- 

 gist), the egg being taken out, and the window-end turned up. 



Examining Iron and Steel. f — Mr. F. L. Garrison considers it is 

 at present difficult to say what will be eventually the practical value 

 of the Microscope in the sciences of engineering. The role which it 

 seems most likely to play is that of an adjunct to the testing-machine, 

 and not (as some have supposed) a rival to the chemical laboratory. 

 That it will be a most valuable accessory seems, to say the least, 

 highly probable. 



As regards preparing the material for examination, the author 

 points out that Mr. J. C. Bayles J has " described the process in such 

 a plain and comprehensive manner, that if his instructions are care- 

 fully followed, one need not encounter any serious obstacles after a 

 little experience and the expenditiu'e of a considerable amount of 

 time and patience. Patience and cleanliness are the two most 

 important attributes to be acquired by a student, if he desire success 

 in a work of this characrer. A deficiency in either will be sure to 

 spoil his work, and in the end he will give it up in disgust, wondering 

 what has been the cause of his failures. In grinding the specimens, 

 it is quite unnecessary that they should be ground to an extreme 

 thinness and mounted in Canada balsam, as microscopical objects are 

 usually preserved. This entails a vast amount of labour, to no end 

 whatever. A good and accurate photograph, once obtained, is usually 

 sufficient for any reference that might be desired in the future ; 

 besides, with a little care the etched surfaces of the objects can be 



* Nature, 1886, p. 497. See this Journal, v. (1885) p. 784. 

 t Joum. Franklin Institute, cxx. (1885) pp. 300-6 (5 pis.). 

 X See this Journal, iii. (1883) p. 605. 



