ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 729 



Theiler and Soil's (J/.) Demonstration Microscope. 



[Same as AVaecliter's or Engell's, Vol. 11. (1SS2) p. 398.] 



Knowlalje, VII. (1885) p. 491 (1 fig.) 

 Nature, XXXII. (1885) p. 112! 

 „ „ TIniversal Pocket Microscope. [Supra, p. 704.] 



Ibid., p. 491. Ibid., p. 112. 

 ToLMAN, H. L. — Eye-piece Micrometers. [Supra, p. 704.] 



Amer. Mon. Micr. Journ., VI. (1885) pp. 115-6. 

 See also under " Measurements of Blood-corpuscles," 

 The Microscope, V. (1885) pp. 113-4, from the Lejal News. 

 Van Brunt, C. — Diatoms mounted in Prof. Smith's newest medium— Photo- 

 graphs of same. Joum. N. York Micr. Soc, I. (1885) pp. 102-3. 

 Wales, W. — The proper care and use of Microscope Lenses. [Supra, p. 708.] 



J'jid., pp. 113-6 and'l23. 

 Ward, R. H. — Recent progress in the Improvement of the Microscope. 



from Annu.d C'ljciopcdia for 18S4 (New York, 1885) pp. 499-522 (42 figs.). 

 „ „ See Belirens, J. W. 



Westien, H.— Apparat zur Vergleichung symmetrischer Stellen der Schwimm- 

 haut des rechten und linken Fusses vom Frosche. (Apparatus for tho comparison 

 of symmetrical parts of the webs of the right and left feet of the frog.) 



[I'ost.^ Zeitschr. f. Instrumentenk., V. (1885) p. 198 (1 fio-.). 



B. Collecting, Mounting and Examining Objects, &c. 



Preparing Embryos.* — The method of examination which Dr. L. 

 Lowe employs is as follows : — The embryos are placed, accordino to 

 their size, in a 1 per cent, to a saturated solution of bichromate of potash, 

 which is frequently changed. They remain in this for several months 

 or a year. After being thoroughly washed in water they are stained 

 in a 1 per cent, solution of carmine, which is renewed as soon as its 

 ammoniacal odour is lost, then again washed, soaked in glycerin- 

 jelly in an incubator (1-4 weeks), and hardened in alcohol. Sections 

 are then cut with a microtome. 



Methods of Investigating Animal Cells.t — The methods of exa- 

 mining living animals, e. g. Amcebce, Infusoria, &c., under the Micro- 

 scope, are first described by Di-. A. Brass. When they have been 

 studied in their natural state, various reagents are applied to the living 

 object ; e. g. a mixture of chromic acid, 1 ; platinum chloride, 1 ; con- 

 centrated acetic acid, 1 ; water, 400-1000 ; hyperosmic acid, pici-o- 

 sulphuric acid, or concentrated solution of corrosive sublimate. Brass 

 believes, however, that better results are obtained by studying protozoa 

 withoTit reagents or staining. 



The free cells of the animal body are examined in the living state 

 on a warm stage in lymph fluid, vitreous humour, iodized serum, or 

 • 6-0 • 7 per cent, salt solution. Tho ova of mammalia are examined 

 on a warm stage in lymph, to which a trace of sodium carbonate has 

 been added. 



Animal tissues are examined in tho fresh state in 0*G-0-7 per 

 cent, salt solution, iodized scrum, or lymi)h fluid. The ajjplication 

 of water is to be avoided, as it alters tho cells. Tissues, of which tho 

 internal structure is to be examined, are washed, after treatment with 



* ZcitHchr. f. Wiaa. Mikr., i. (1884) pp. 585-6. 

 t Ibid., pp. 39-51. 



