1892.] THE MICEOSCOPE. 117 



Histology, Seller's (C.) work is good, and Fraenkel & Pfeiffer's 

 Micro-photographic Atlas of Bacteria, Berlin. 



I do not think Andrew Pringle's work at all adapted for be- 

 ginners, or even for moderately advanced students, as is so often 

 recommended, the apparatus and methods being too extensive. 

 For advanced workers it is a valuable work. 



If any readers of this article will give aid by criticisms of good 

 works, noting their good points, there might be a good deal 

 learnt and much assistance rendered to all students of microscopy. 



The Care of a Microscope. 



By EDWARD BAUSCH, 



ROCHESTER, N. Y. 



[From Manipulation of the Microscope , pp. 107-g.] 



Besides acquiring the ability to properly use an instrument with 

 its accessories, it is important to know how to keep one in the 

 best working condition. It may be said without reserve that an 

 instrument properly made at the outset and judiciously used 

 should hardly show anv signs of wear either in appearance or in 

 its working parts even after the most protracted use ; and further 

 than this, every good instrument should have a provision for tak- 

 ing up lost motion, if there is a likelihood that this may occur in 

 any of the parts. 



Especial care should be given to the optical parts, in fact, such 

 care that they will remain in as good condition as when first re- 

 ceived. Accidental injury may of course occur to them, but if a 

 systematic manner of working is followed and a special receptacle 

 for each part is provided this mav usuallv be avoided. The fol- 

 lowing rules refer mainly to the instruments manufactured by the 

 Bausch & Lomb Optical Co., but are applicable to instruments 

 in general. 



To Take Care of a Stand. — One of the first rules should be 

 to keep the instrument free from dzist. If dust settles on any 

 part of the instrument, remove it first with a camel's-hair brush, 

 and then wipe carefully with a chamois skin, uoith the grain of 

 the finish and not across it, as in the latter case it is likely to 

 cause scratches. Keep the working and sliding parts absolutely 

 free from dust, as this grinds and will thus soon cause play. 



Use no alcohol on any part of the instrument, as it will re- 

 move the lacquer. As the latter is for the purpose of preventing 

 oxidation of the metals, it is important to observe this rule. 



In using the draw-tube impart a spiral motion. In instruments 

 which have no cloth lining, a straight up-and-down movement 

 should be employed, as the tube w^ill otherwise become scratched. 

 If it becomes necessary to lubricate any of the parts, use a slight 

 quantit}" of soft tallow or good clock oil. 



In an instrument which is in constant use it sometimes occurs 



