339 
ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
compared numerically with those obtained with the Lick photographic 
objective. 
Photomicrograph v. Microphotograph.* * * § — Dr. A. C. Mercer, in the 
present note on his paper of 1886, points out that the word photomicro- 
graph was first used in 1858. An account of its origin is to be found 
in the ‘Liverpool and Manchester Photographic Journal’ (now ‘ British 
Journal of Photography ’), August 15, 1858, pp. 203 and 414 ; also in 
1 Sutton’s Photographic Notes,’ iii. pp. 205 and 208. 
Advances in Photomicrography. t — Herr G-. Marktanncr-Turneret- 
scher collects together under this title a series of abstracts of recent 
papers relating to Photomicrography ; these have already been noticed 
in this Journal. 
(5) Microscopical Optics and Manipulation. 
Multiple Images in Mirrors.J — Mr. W. B. Stokes explains the origin 
of multiple images seen in plate-glass mirrors. The brightest image is 
due to reflection from the silvered back, another to reflection from the front 
glass surface, and others are due to more than one reflection within 
the glass. When the mirror is rotated in its own plane, these images 
will change their position, owing to the fact that the surfaces of the plate 
are not truly parallel. For a particular angle of inclination of the two 
surfaces of the plate, the first two images may be made to coincide. 
33. Technique. § 
(1) Collecting- Objects, including- Culture Processes. 
Apparatus and Method of Manipulation for the Preparation of 
Roll Cultures of Anaerobic Organisms. ||-In using the apparatus invented 
by Mr. E. E. Ewell (fig. 31), the tube is inoculated with the requisite 
number of organisms in the usual way, and is placed in the water-bath 
B, the temperature of which is kept at some convenient degree between 
the solidifying point of the medium and the thermal death point of the 
organism to be cultivated. The cotton plug P is pushed into the tube 
to make room for the rubber stopper carrying the glass tubes a and a\ 
The stopper is carefully sealed with sealing-wax, and the connections 
made with the thick rubber tubes N and 0, the latter being secured with 
wire. E leads to a vacuum service pipe, or to some form of vacuum 
pump ; F leads to a hydrogen gas generator. I and H being closed, open 
L until the air is removed, then close L and open H. The mercury con- 
tained in the bottle 0 passes up the tube D until an equilibrium is 
established where the point at which it comes to rest is marked. If all 
parts of the apparatus are tight, the column of mercury will remain 
stationary ; if it falls, all the connexions must be re-examined. In order 
* Trans. Amer. Micr. Soc., xviii. (1897) p. 131. Cf. this Journal, 1887, p. 665. 
t Jalirb. f. Photographie u. Reproductionstechnik, 1897, 12 pp. and 4 figs. 
j Journ. Quekett Micr. Club, vi. (1897) pp. 322-4 (3 figs.). 
§ This subdivision contains (1) Collecting Objects, including Culture Pro- 
cesses ; (2) Preparing Objects ; (3) Cutting, including Imbedding and Microtomes ; 
(4) Staining and Injecting; (5) Mounting, including slides, preservative fluids, &c. ; 
(6) Miscellaneous. 
11 Centralbl. Bakt. u. Par., 2 te Abt., iii. (1897) pp. 188-90 (1 fig.). 
