100 THE MICROSCOPE. [April, 



difTerences of the schizomycetes, for when he had seen the photo- 

 graphs they showed the plasma balls, etc., to be ordinary zooglaea 

 colonies of micrococci which occur in isinglass jelly." Koch sug- 

 gests, as an example of the inaccuracy of some observers, a com- 

 parison of Zurn's photographs of bacillus arithracis in Zurn's 

 fig. 4. plate II, and figs. 3 and 4, on plate I, with his photograph, 

 No. 6 (Cohn's Beitriige, bd. 2, hft. 3, plate XVI, Xos. 5 and 6), 

 and if the comparison is made by any one who knows photography 

 he will readily recognize that they are putrefactive bacilli. In 

 describing this last photo Koch pointed out the danger of con- 

 founding it with other somewhat similar bacilli. He also re- 

 ferred to the researches on splenic fever and septicaemia (Koch). 

 Semmer in Virchow's Archiv.. bd. 70, S. 371, also gives an ex- 

 cellent example in his researches on pathogenic bacteria. 



Do not think that photography is to take the place of drawing 

 universally ; that can never be, as there are many instances where 

 photography is not possible. 



\_To be co?iiifiued.'\ 



The Microscope in Schools and Colleges. 



By L. W. CHANEY, Jr., 



PROFESSOR OF BIOLOGY IN CARLETON COLLEGE, NORTHFIELD, MINN. 



Ever since the discovery that vision of small objects could be 

 secured by lenses, two uses have been made of the microscope, 

 (i) In the hands of earnest men it has revealed wonders in the world 

 of little things no less marvelous than the more imposing revela- 

 tions of the telescope. (2) In the hands of amateurs desiring satis- 

 fying amusement it has served an admirable purpose. Some of 

 t-he most important improvements in microscope construction 

 have resulted from the enthusiastic devotion of those who entered 

 upon the employment simply as a diversion. These two services 

 rendered by the instrument have been so clearly evident that 

 makers have been influenced by it in the styles which they have 

 adopted and in the accessories produced. Only within a few 

 years has the microscope assumed a place in instruction more im- 

 portant than that of any other instrument. The demands of in- 

 struction differ from those either of investigation or pleasure. 



The investigator seeks new facts, the amateur the beautiful or re- 

 markable in nature ; the student needs confirmation and enforce- 

 ment of the results already worked out. There is at present a 

 considerable tendency toward insisting that the student shall be 

 an investigator. Using the word student in a broad sense, how- 

 ever, it becomes evident that for general purposes of training much 

 better results may be attained by repeating the work of some one 

 else under proper guidance than by trying at once to venture into 



