78 



THE AMERICAN MONTHLY 



[April, 



also to a great extent the statement 

 in reg;ard to the identification of the 

 ^five specimens of blood.' " 



J. B. Treadwell. 



CORRESPONDENCE. 



To THE Editor — Having frequently 

 noticed the perfect ease with which one 

 ■can keep both eyes open when using the 

 binocular as a monocular microscope — in 

 fact, a novice will generally think that he 

 is using both, — I thought that the follow- 

 ing simple arrangement would be of value 

 to those who use the monocular, but who 

 have not learned to keep both eyes open, 

 as is recommended, while using only one 

 at the tube. Indeed, there are many 

 persons who find it a very diificult matter 

 to do this. I am convinced that the 

 fatigue, and often pain felt after using the 

 microscope is almost entirely due to the 

 closing of the eye not in use. (In some 

 •cases it is caused by too intense or too 

 feeble illumination.) 



The arrangement is simply a blackened 

 piece of sheet-brass, cut to the required 

 shape and attached to the eye-end of the 

 microscope-tube in the manner best suited 

 to the instrument. A convenient way is 

 to attach it to the cap of the eye-piece. 

 The eye not in use may then be kept open 

 with perfect ease, and will not receive 

 images of external objects to interfere 

 with the image in the other eye. 



Edward Pennock. 



[Mr. Pennock has kindly sent us one of 

 the shades mentioned in his letter, as 

 made by Messrs. J. W. Queen & Co., and 

 it certainly is the best thing we have ever 

 seen for the purpose. — Ed.] 



NOTES. 



— The long-expected book of Professor 

 J. Edwards Smith, " How to see with the 

 Microscope," is now in the hands of a 

 publishing house in Chicago , and is 

 expected to be out in March. We look 

 to its publication with much interest, and 

 will give our readers early notice of its 

 contents. 



— A sixth edition of Carpenter's excel- 

 lent book. The Microscope and its 

 Revelations, is in preparation, and will be 

 ready next fall. The fifth edition is out of 

 print. 



— The Medical Record c\\.ts an instance 

 of the discovery of Trichinae in fishes. 

 Near Ostend, on the North Sea, the 

 worms were found in abundance in the 

 flesh of fishes. It is supposed that they 

 had eaten of the offal in the harbor. 



— An exceedingly interesting and valu- 

 able paper by D. D. Cunningham, entitled 

 " On certain effects of Starvation on 

 Vegetable and Animal Tissues," is pub- 

 lished in the January number of The 

 Quarterly Journal of Microscopical 

 Science. The experiments on vegetable 

 tissues were conducted by cultivating cer- 

 tain Fungi {Choa7iephora, and Pilobolus 

 crystallimts) in various ways ; and for the 

 study of animal structures, larvae of the 

 toad, Biifo nielanostictiis, and of Rana 

 tigrina, were chosen. We regret that we 

 can only direct attention to this article, 

 not having space to notice it more fully. 



— Mr. H. F. Atwood, in a private letter 

 to the Editor, writes as follows : " I am 

 using something new in the way of aquaria 

 for Entomostraca, and it works well and 

 makes rather unique ornaments for the 

 window. I use the glass balls such as 

 sportsmen use for trap-shooting. The ones 

 now hanging in my window are of blue 

 glass, and the Entomostraca are doing 

 well, propagating fast, and of course are 

 quite conspicuous, owing to the balls 

 magnifying somewhat. Half a dozen 

 hung in the window present a rather 

 pretty appearance, and I have different 

 famihes in each." It has suggested itself 

 to us that by using such glasses of differ- 

 ent colors, some interesting comparative 

 experiments might be made on the effect 

 of colored light upon the growth and mul- 

 tiplication of various microscopic organ- 

 isms. 



— We have lately received " A Con- 

 densed List of a few of the Most Desirable 

 Microscopes, of moderate cost, and ac- 

 cessories, mounting implements and ma- 

 terials," etc., from Messrs. R. & J. Beck, 

 of Philadelphia, and also a " Supplement- 

 ary Catalogue of new and second-hand 

 Microscopes, Microscopic Apparatus and 

 Telescopes," from Messrs. J. W. Queen & 

 Co. Those who intend to purchase such 

 apparatus would do well to send for both 

 of these pamphlets. 



