^OOLOGY AND BOTANY, MICROSCOPY, ETC. 471 



when tlie first coat is applied. Cells built up entirely of it are as 

 colourless as the glass itself. 



FinisMng Slides.* — The only factors, says Miss M. A. Booth, to be 

 taken into account for filling up the distance from slide to cover-glass 

 without spreading, are a proper cement and the proper consistency of that 

 cement. Let us assume that the cell is of block tin, and firmly attached 

 to the slide by shellac cement or by gold size or marine glue, and so 

 thoroughly dried that the cell cannot be moved on the glass by the 

 vigorous use of a file. Where strength is not required, no cement is so 

 convenient as asphalte or Brunswick black for rounding out the wall, 

 and if applied at one operation there is nothing treacherous about it. 

 But never put a fresh coat over a partially dried one. 



Where it is desired to reinforce the cement which attaches the cell 

 to the slip, the cement should be used pretty thick, and it is well to 

 keep two bottles of each kind of cement, one a fresh and therefore thin 

 one, and another from which the solvent has partially evaporated. 

 With most cements it is best that they should be applied in successive 

 coats, allowing time for each to dry before the next is applied. With 

 cement of a proper thickness and a penknife to turn up the cement 

 towards the cell, while the turntable is revolving, filling up the distance 

 from slide to cover-glass is quite easy. 



Lyon, H. N. — Cements, Varnishes, and Cells. 



Tlie Microscope, IX. (1889) pp. 69-74. 

 Zabkiskie, J. L. — A Nest ofWatcli-glass Covers. 



Journ. New York Micr. Sac, V. (1889) pp. 76-8 (3 figs.). 



C6) Miscellaneous. 



Counting the Colonies in an Esmarch Plate.f — Where it is desirable 

 to make an accurate enumeration of the number of colonies developed on 

 an Esmarch plate, and where these are not very numerous. Dr. Tavel adopts 

 the following method. The tube to be counted is pushed slowly and with 

 a screw-like motion into an Esmarch enumerator, and at the same time a 

 glass rod is fixed to its clamp, so that a spiral line is traced upon the 

 glass, the turns of which are about 1 cm. distant from one another. 

 The counting is done by following with a lens the course of the spiral 

 from its beginning to its end. In this way the risk of counting a 

 colony twice over is prevented. 



B E N E c K E, F. — Die Bedeutung der mikroskopischen Untersncliung von Kraftfutter- 

 mitteln fiir die landwirthscliaftliclie Praxis. (The importance of the microscopical 

 investigation of strengthening-fodder for practical agriculture.) 



15 pp., 8vo, Dresden, 1888. 

 Bi DWELL, W. D. — A Land Title settled by the Microscope. 



[Examination of some lead-pencil memoranda alleged to be of different dates.] 



Amsr. Man. Micr. Journ., X. (1889) p. 60. 

 B ROWN, F. W. — A Course in Animal Histology. IX. 



[Muscle.] Tlie Microscope, IX. (1889) pp. 81-2. 



Fkeeborn, G. C— Notices of New Methods. VIII., IX. 



Amer. Mon. Micr. Journ., X. (1889) pp. 66, 79-80. 

 Tate, A. N. — The Application of the Microscope to Technological Purposes. 



20th Ann. Rep. Liverpool Micr. Soc, 1889, pp. 6-9. 

 Whelplet, H. M. — Microscopical Laboratory Notes. 



Amer. Mon. Micr. Journ., X. (1889) pp. 65-6. 



* Micr. Bulletin, vi, (1889) p. 8. 



t Centralbl. f. Bakteriol. u. Parasitenlc, v. (1889) p. 552. 



