28 THE MICROSCOPE. 



wrong time. The cement-cells should be quite dry and hard before 

 mounting, or a dewiness will appear and ruin the object. Soften 

 the cement over the lamp, press the cover down till it sticks all 

 round, let stand a day or two, and finish off. No doubt the diatoms 

 would be more secure if burnt on the cover in the dry mounts, and 

 possibly that orocess would be sufficient for the balsam mounts 

 without the film of isinglass, as stated on p. 68 of Davies' Manual of 

 Mounting. — From the Journal of the Victoria Microscopical Society. 



The Rela tions of Micro-Organisms to Disease. — W. T. 



Belfield, M. D., in a lecture before the Alumni Association, College 

 of Physicians and Surgeons, New York {New York Medical Journal, 

 February 24 and March 3, 1S83), says that he had chosen the sub- 

 ject simply because of its intrinsic interest and importance, and also 

 because there existed in the mind of the medical publidn this coun- 

 try a divided opinion regarding it, which seemed to him not to be 

 warranted by the facts. 



The study of micro-organisms is an excessively difficult one, 

 owing to the need for the proper facilities in pursuing investigations 

 in the laboratory, and the amount of time and expense required to 

 carry on the work intelligently. There is a tendency for the profes- 

 sion to treat the subject as a trivial or fanciful one, and in general 

 to ignore it. Bacteria have been observed as early as 1675, but 

 they suddenly acquired an interest to pathologists in i86r, when 

 Pasteur endeavored to show a genetic relation between plants and 

 diseas( - 



Conn's definition of bacteria, formulated in 1875,1s still ap- 

 plicable, "Cells devoid of chlorophyll, spherical, oblong or cylin- 

 drical, which reproduce themselves extensively by transverse divi- 

 sion, and live either isolated or in families." Nutrition and assimi- 

 lation were carried on by a process of osmosis. 



Their simplicity of organization explains their extensive distri- 

 bution throughout nature. 



Certain errors in manipulation and misinterpretations of facts, 

 which were so liable to take place even with the greatest care and 

 most improved facilities for investigation, would account for the 

 serious mistake made by Pasteur and others in saying that bacteria 

 were capable of spontaneous generation; there is no reason to sup- 

 pose that bacteria, like all other organisms, do not always proceed 



