The Microscope. 95 



what of a feat for the microscopist as well as for the objective. 

 Knowing these facts, would it not be surprising to have those 

 delicate lines beautifull}^ resolved with a 1-5 inch objective? It 

 can be done with a dry 1-5 of 135° aperture, and conspicuously 

 done. It is amusing and pleasing and true. The objective is 

 by Gundlach, and in the resolving of Amphipleura there is no 

 trick and no catch ; the resolution is made by oblique light, and 

 with the two-inch ocular. But although there is no trick, all 

 being as plain and above board as possible, there is an import- 

 ant secret. This is in the mounting medium. The refractive 

 index is the secret. The higher that is the more readily will 

 the resolution be made. That of the medium at my disposal is 

 2.30, so marked bj"^ the mounter of the slide and originator of 

 the medium, the lamented Dr. Allen Y. Moore, a microscopist 

 who died too early ; too early in years, too early for the good 

 of the microscopical world, and far too early for those who were 

 attached to him, as was the writer. But in a medium of such 

 an index this excellent objective will resolve Amphipleura, and 

 do it with great brillianc3\ I do not doubt the success over a 

 similar medium, of other American objectives of this focal 

 length and angle, but it is with this special lens that I have had 

 the pleasure of repeatedly making the resolution. 



An Amateur. 



PVBLI CAT IONS 



Practical Pathology and Morbid Histology. — By Heneage 

 Gibbes, M. D., Professor of Pathology in the University of 

 Michigan ; 8 vo., pp. XI, 320. Philadelphia: Lee Brothers & 

 Co. " The following pages," the author sa^^s in his preface, 

 " are not intended to form an exhaustive treatise, but to cover 

 the essential points with which the student must become 

 familiar in the work of a pathological laboratory-. Such in- 

 structions are given as will enable him to transfer a specimen of 

 any morbid change directly to his microscope in an unaltered 

 condition, and to recognize it unerringly." The author has ac- 



