ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 483 



stands, and the lenses of many manufacturers. I have had, therefore, 

 opportunities to test the practical convenience and advantages of the 

 many sorts of Microscopes which the students have brought along with 

 them. The result of this experience is the conviction that it is un- 

 desirable to recommend a student to purchase any Microscope whatsoever 

 of American manufacture, and to always counsel him to obtain, if possible, 

 one of the German or French instruments. 



" In order to make my judgment more clear, I may add that I know 

 of no American Microscope which I should like to purchase at any 

 price, for my own use in histological or embryological work. 



" I venture to express this adverse opinion in regard to American 

 Microscopes in the hope of inducing some of our opticians to manu- 

 facture a stand for a Microscope suitable for the use of students of 

 histology and biology. It appears to me that the simple model now 

 almost universally adopted in Europe is far superior to everything 

 oifered us in rivalry to them by our own dealers. 



" To justify myself, I should like to give, first, the reasons for my 

 disappi'oval of the American forms ; and, second, the reasons for my 

 preference of German forms. The fundamental error in Microscopes of 

 American manufacture is that they are for the most part constructed 

 with a view of, I might almost say, entrapping inexperienced purchasers. 

 The zeal of the maker is turned too much to decorative lacquering and 

 nickel-plating ; he adds to his stand as great a variety of mechanical 

 contrivances and adjustments as the price of the stand will permit, and 

 many of these contrivances are not really commendable for their utility. 

 In the majority of cases the stands are made to tilt, which, for one that 

 uses the Microscope for real work, is an almost useless luxury, because 

 he who really works in histology necessarily examines fresh specimens 

 in fluids, or at least constantly has on the stage of his Microscope 

 preparations in various stages of unreadiness, and not mounted in a 

 permanent form. All this implies the constant use of fluids, and, if the 

 stage of the Microscope is inclined, the use of liquids is impracticable. 

 Any one, therefore, who uses his Microscope for the ordinary purposes 

 of a student or an investigator, or in connection with clinical or patho- 

 logical work, very soon falls out of the habit of tilting his Microscope. 

 Hence it is, that, while making a Microscope to tilt renders it consider- 

 ably more expensive, it adds nothing essential to the convenience of the 

 stand for laboratory work. This same fact, that most of the work must 

 be done with the tube of the Microscope vertical, renders it indispensable 

 that the Microscope should not be too high ; so that we must put down 

 the ten-inch tube as a bad feature for a student's Microscope. A rack 

 and pinion is undoubtedly advantageous ; it renders the use of the 

 Microscope more convenient, and increases its durability by diminishing 

 the strain upon the stand during the coarse adjustment of the focus. 

 When this adjustment is effected by shoving the tube with the hand, the 

 Microscope wears out sooner than with the rack-and-pinion movement ; 

 yet even the rack and pinion, which are so generally put on our American 

 Microscopes, are not indispensable, and the greater part of the histo- 

 logical and embryological investigations of the past twenty years have 

 been made without the employment of this convenience. 



" The stage of the American Microscope is very faulty. The large 

 movable glass plate with a hole through it is a toy fit only for an 

 amateur or fancy collector ; it interferes with the use of fluids, and with 



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