SUPPLEMENT. 359 



1877. January, " Wenham's Reflex Illuminator," p. 74.; 



" R. Hitchcock, Esq., vs. High Angles," p. 504. 

 The past contributions to the American Journal of Microscopy 

 will, owing to the kindness of Prof. Phin be given in full. 



PROF. R. HITCHCOCK VS. HIGH ANGLES. 



In the May number of the American Journal of Microscopy , 

 I find an article containing a good-natured criticism of a paper 

 read by me before the Dunkirk Microscopical Society last 

 October. 



Mr. Hitchcock candidly states that he has only seen a short 

 abstract of this paper, and has but an imperfect knowledge of 

 it. He further suggests that his main object was to call further 

 attention to my views, and he suggests that I put them in form, 

 so as to be published iu the American Journal. 



For the benefit of Mr. Hitchcock, I will state, that my views 

 have been clearly stated in a series of articles, which have been 

 published in the Cincinnati Medical News during the past three 

 years, under the caption of "High us. Low Angles," and have 

 thence been quoted from and reprinted in various publications ; 

 certainly I cannot be expected to go over the ground anew at 

 this late day. It is true that I exhibited before the Dunkirk 

 Microscopical Society the No. 20 of the balsam Moller probe 

 platte, and also the 19th Nobert band, both so plainly that all 

 who were present saw without difficulty. These tests were not 

 difficult for the glasses employed, as was attested by the fact 

 that they were shown in a crowded room, amid the attendant 

 jars and vibrations, my object being to demonstrate the facility 

 with which my Tolles' duplex glasses handled these so-called 

 difficult tests. 



To show the work of these same lenses by central light, I 

 selected the same test,iVay. Angulatum which the biological 

 committee at Philadelphia has declared impossible to be shown 

 at a less angle than 20 degrees from axis, with any medium 

 power glass. This test was displayed illuminated by light 

 through a central aperture placed close to the object, just large 

 enough to light the field, the diameter of the aperture being 



