278 THE AMERICAN MONTHLY [December, 



technique in such cases (fixing, staining, bleaching, and mounting). 

 No person who has any regard for his reputation as a micrbscopist 

 would undertake to diagnose for certain bacilli of tubercle from other 

 similar forms existing in water, urine, or any other medium whatever, 

 whether with a magnification of 200 or 2,000 diameters. The property 

 of taking certain aniline stains, and retaining thern so firmly that 

 even nitric acid diluted with only three volumes of water or alcohol 

 will not bleach them, is one peculiar to the tubercle bacillus, and shared, 

 as far as we know, by the bacillus of leprosy only. This test, along 

 with isolation and pure culture, alone makes the recognition of bacil- 

 lus tuberculi certain. 



For search of tubercle bacilli and study of the same, we have found 

 a one-tenth homogeneous immersion objective with a two-inch eye- 

 piece (approximately 500 diameters) the most satisfactory and least 

 tiring to the eye. A good one-eighth, however, with the same eye-piece, 

 should be quite sufficient. — National Druggist. 



QUERIES. 



Putting the Maker's Name on Objectives. 

 In reply to the question of a subscriber as to the custom both at 

 home and abroad with reference to putting maker's names on objec- 

 tives, we have the following statements from several of our leading 

 dealers : 



1. By the Bausch & Lomb Optical Company. 



All reputable makers of objectives both in this country and abroad 

 have their names engraved on objectives, which is a guarantee for the 

 quality of the lens. There are some microscope objectives made in Eng- 

 land and France which are sold with the cheap imported microscopes 

 brought into this market by importers of optical instruments which 

 bear no inscription as to who the maker is. 



2. By W. H. Bulloch, Chicago, 111. 



I do not know of any maker of first or second-class objectives in 

 this country or abroad, who does not put his name either on the ob- 

 jectives or box. Any person who makes any pretention to microscopy 

 will not usually purchase an objective unless the maker's name is on it. 

 It is said that a workman is known by his tools ; and so far as I have 

 had any experience with those who use the microscope, if they cannot 

 give the maker's name of the objectives or instrument, they are unwor- 

 thy of being known as microscopists. 



3. By G. S. Woolman, New York City. 



The custom in the United States is to put the maker's name either 

 on the objective itself or on the box. Occasionally on the low-priced 

 lenses the name is omitted. The French objectives quite often reach 

 this country without name. The German custom is the same as the 

 United States. A buyer can rely upon obtaining the make required it 

 he orders from any reliable house here. The English first-class makers 

 do the same as the United States. There are, however, a number of 

 very fair English objectives made that do not have names upon them. 



4. By James W. Queen & Co., Philadelphia. 



Custom varies very much among the different makers. The pi'inci- 

 pal makers in this country generally place their names upon the ob- 



