ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 



89 



is a novelty, as both the above writers used prisms. The distinctive 

 feature of the gratings is thnt the spectra with the order of tbeir colours 

 reversed can be superposed, whilst with a prism the suporposed spectra 

 would both have their colours in the same order, i.e. red ends both on 



Fig. 10. 



B 



the same side. The former arrangement has an obvious interest of its 

 own, because of the comparison it affords of colour sensation produced 

 by a series of pairs of colours, each pair of which has the same wave- 



length. 



(6) Miscellaneous. 



Fobgax, W. — Simple Method of obtaining a Large Field of View with the Com- 

 pound Microscope. 



[The enlarged field of view caused by closing the draw-tube is simply a result 

 of the reduction in power.] Proc. Scottish Micr. Soc, iii. pp. 32-4 (1 fig.). 



B. Technique.* 

 (1) Collecting- Objects, including- Culture Processes. 



Simple Method for Cultivating- Anaerobic Bacteria in Capsules. f — 

 Dr. St. Epstein describes a very simple procedure for cultivating 



Fig. 11. 



anaerobic bacteria. A Petri's double capsule is fixed round with a broad 

 rubber band having a couple of rubber tubes at opposite sides. The 



* 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. ' f Centralbl. Bakt., 1" Abt., xxviii. (l'JOO) p. 443 (1 fig.). 



