78 



THE AMERICAN MONTHLY 



[April, 



CORRESPONDENCE. 



On Objectives. 



To THE Editor. — I quote from your 

 issue of February, p. 28, as follows : — 



"Is it possible to throw light on such 

 a confusing subject .-' " 



" Why should a physician who uses a 

 microscope in his practice pay $35 for 

 one objective while the $15 one will an- 

 swer his purpose just as well ? " 



He would be a fool to do so, but he 

 will never know that, you cannot con- 

 vince him until he tries both for himself. 

 No man knows for certainty which is 

 best for another man. The enclosed let- 

 ter from the late Dr. Hoyt, an experi- 

 enced practitioner who had used for 

 diagnosis and pathology for years the ob- 

 jectives in common use by the profession 

 — shows the difference in results be- 

 tween first quality and $15 lenses, and 

 throws some light on this confusing sub- 

 ject. Carl Reddots. 



[copy of letter.] 



" To-day I had for examination a speci- 

 men of urine that contained albumen, 

 and casts almost invisible with common 

 objectives. This evening I have been 

 looking at them with the -^^ [Tolles 180°]. 

 It shows them splendidly and leaves no 

 doubt of their nature. It is just what 

 every physician needs who does not wish 

 to grope in the dark." 



[We do not print the above corres- 

 pondence for the purpose of controversy ; 

 but because we are well aware of the in- 

 fluence of reiterated dogmatic assertions, 

 even when they are demonstrably erro- 

 neous. Not every one who is interested 

 in this subject — and all who purchase 

 objectives are, — has the opportunity of 

 submitting the matter to a test. Nor is 

 it necessary that he should. One has 

 only to look at the work that has been 

 done in the past, before excessive angu- 

 lar apertures were used at all. What 

 does the writer mean by saying " No 

 man knows for certainty which is best 

 for another man ?" Either what is good 

 for one man is good for another for the 

 same purpose or else we have no crite- 

 rion of excellence. The reason the argu- 

 ment of our correspondent is inconclusive 

 and unsatisfactory, is simply that the facts 

 offered in support of it are not accepted. 

 It is absurd to say that hyaline casts — 

 no matter how hyaline they may be — 



can be better examined with a lens of 

 high angle than with a good objective of 

 moderate angle. It is an old and rather 

 worn out claim, which needs no refuta- 

 tion except such as anyone can gain by a 

 little experimenting. — Ed.] 



To THE Editor. — " M. A. B." who 

 has a large exchange-list, should tell 

 from where the damaged slides come, 

 to warn others. During the eighteen 

 months in which I have exchanged I 

 have yet to receive a broken slide, or to 

 hear of one broken that I have sent out. 



I use the wooden boxes, and when I 

 send out slides I send stamps to pay for 

 the return of the empty boxes, which costs 

 about one cent for each box of six slides. 

 1 use tissue paper which I wrap around 

 the slides several times until it fits very 

 tight into the grooves in the box, so tight 

 that the slides have to be forced in with 

 some pressure. " M. A. B." should try 

 this way. T. C. 



Richmond, Va. 



A Work-table. 



To THE Editor. — As universally re- 

 commended, I have been in the habit of 

 keeping my microscope under a large 

 bell-glass. The largest I could find out 

 here would barely cover the instrument 

 and the bulls-eye condenser, thus requir- 

 ing the other articles to be put away out 

 of the dust when not in use. The bell- 

 glasses are costly, and easily broken. I 

 finally had a box arrangement made on 

 top of my work-table. Its internal height 

 is 18 inches. There are two strong up- 

 rights let through the top and screwed 

 to the hind legs of the table. The back 

 is stationary, and is screwed on the out- 

 side of the two uprights ; the sides swing 

 by hinges from the back ; the top is also 

 hinged to the back and opens upward, and 

 the front is in turn hinged to the top. 

 The sides are tongued to fit into grooves 

 in the top and front. Some small shelves 

 are arranged against the back. 



T. B. Jennings. 



A Correction. 



To the Editor. — Will you kindly 

 allow me space for the correction of two 

 or three errors which I have noticed in 

 my paper on the " Conditions of Success 

 in the Construction and the Comparison 

 of Standards of Length," read at the 

 Elmira Meeting of the American Society 



