1894 THE MICROSCOPE. 91 



4. The executive committee may provide for occa- 

 sional formal papers and addresses, or longer commun- 

 ications, from members or others, and the titles of them 

 are in all cases to be previously placed on the program 

 on the blackboard, with the time (approximately) to be 

 occupied. 



5. After the roll-call and the papers, if any, the re- 

 mainder of the session shall be informal, each member 

 examining the specimens and apparatus in which he may 

 be most interested. In this part of the session no " order" 

 shall be observed or maintained. 



6. At 10 o'clock the President shall declare the meet- 

 ing adjourned. 



Our Instrument in the study of Natural History. -The 



report of the recent Conference on Natural History rendered to 

 the Committee on Secondary Studies of the N. E. A., constantly 

 emphasizes the use of the microscope. See 



Pa^e 151 (among the necessities for proper Botanical work). 

 "Table room, a good compound microscope magnifying from at 

 least 50 to 300 diameters, and a few ordinary re-agents should 

 be furnished each pupil." 



Page 161 (Physiology). " Demonstrations of the histological 

 structure of the various organs require the use of a good micro- 

 scope, with powers of four or five hundred diameters. It will 

 add greatly to the interest if the teacher is able to make a por- 

 tion, at least, of such preparations in the presence of the class. 

 If the possession of a number of microscopes renders it possible, 

 it is very desirable that an opportunity be afforded students for 

 making for themselves preparations." 



Page 154 (Zoology). "The microscope may well be em- 

 ployed in calling attention to the structure of the scales (of the 

 fi^h). No better object will ever be found for exciting interest 

 among young naturalists than these scales exhibited by polar- 

 ized light." 



Centrifugation — to separate sediment, is coming into gen- 

 eral use among European investigators. A number of instru- 

 ments are in use for the purpose. 



