1894 THE MICROSCOPE. 185 



CORRESPONDENCE. 



A Reply to Dr. Alfred C. Stokes' Critical Communica- 

 tion, headed " A Note incidently in regard to the Ani- 

 mality of the Diatom, but especially to Mr. Cunningham's 

 method of illumination. — I have duly noted an article under 

 the above caption published in the Oct. number of this periodial 

 coming from the pen of the distinguished Micrographer, Dr. 

 Alfred C. Stokes. Its appearance, as well as its constrution has 

 all the portentiousness of a thunderbolt hurled from Jovian 

 heights. 



In a more concise vein of thought, and more to the point; Dr. 

 Stokes' article in my opinion does not rise to the dignity of legi- 

 timate criticism ; but is more properly that form of critical com- 

 position characterized as a " diatribe," for which there is neither 

 excuse, pretence or justification ; as based upon anything oc- 

 curring in my article. Every point that he was pleased to find 

 fault with has been reasonably met in my article ; by implication 

 at least, if not in a more cursive manner, and my failure to 

 make some reference to a Homogeneous Oil immersion lens, 

 and chip in a little about the " critical illumination," ought not 

 to indicate on my part any real ignorance of the system of 

 lenses, and illumination more particularly adapted to the study 

 of recent Bacteriology. What Dr. Stokes proposed to substitute 

 for the methods used by myself and suggested by me to others ; 

 belongs more to the limited number of workers who provide 

 themselves with either Apochromatic ; or Oil immersion lenses 

 to be used more particularly for special purposes, such as the 

 resolution of the most diflScult tests, Amphipleura, &c., and 

 when this stage is reached they are often happy and contented 

 in the possession of lenses, of which occasionally a possessor of 

 one ostentatiously announces its angle, resolving power, &c., 

 which sends a wave of envious desire pulsating over the micro- 

 scopical horizon(?) I might have felt the sting of the want, if 

 it had not been that in a former day, I had received directly 

 from Carl Reichert's own hand, one of his 1-15 inch., Homogene- 

 ous Oil immersion lenses, with its appropriate hemispherical 

 immersion illuminating lens to be applied directly in contact 

 with the slide. A record of its use and application in the study 



