PRACTICAL BACTERIOLOGY. 



strument, to which subsequently it may be possible to 

 add whatever is necessary, as the need arises. In the 

 first place it is absolutely necessary that the stand 

 should be jointed, and that it should be provided with 

 coarse and fine adjustments, with rack and pinion, 

 with a micrometer screw, with an Abba's condenser 

 and an iris diaphragm, and above all, with as large an 

 object stage as possible. If later on it is desired to 

 take microphotographs, it is best to get an apochro- 

 matic lens, as far better results can be obtained by its 

 means. However, these lenses are very dear, and 

 cannot be afforded by every one. 



The best microscopes are furnished by Zeiss in 

 Jena,* but they are much more expensive than those 

 manufactured by other firms. Seibert, in Wetzlar, 

 supplies instruments which are very similar to those 

 of Zeiss, and are much cheaper. It would be a good 

 thing if this firm of manufacturers would arrange to 

 have the micrometer screw above as in Zeiss' instru- 

 ments, as when it is underneath it is inconvenient to 

 use. The following firms also supply good micro- 

 scopes : — 



Paul Wachter, Berlin. 

 Otto Himmler, Berlin. 

 A Meyer & Co., Enge-Zurich. 



* London Agent, R. Kanthack, 21, Golden Square, Regent 

 Street, W. 



