ZOOLOGY AND BOTANY, MICBOSCOPY, ETC. 



101 



the drawing. Other adjustments permit the body of the Microscope to 

 be placed in a horizontal or any other desired position. . . . With the 

 instrument described, any portion of the integument, from the scalp 

 to the sole of the feet, can be conveniently examined, and a prolonged 

 examination can be made without fatigue to the observer. It is an 

 instrument which I cannot too highly recommend to those desiring a 

 thorough knowledge of the surface aspect of the skin and its lesions." 



Robin's Dissecting Microscope. — This (made by MM. Nachet) is 

 shown in Fig. 13, with their erecting eye-piece. The stage is arranged 

 so as to provide rests for the hands on either side of the dissecting 

 plate. 



Brucke Lens. — A description of this lens (Fig. 14), much in use 

 on the Continent, does not appear in any of the English books on the 

 Microscope. We take the following from M. Eobin's treatise.* 



" To remedy the inconvenience of the lens being too close to the 

 object in all but low powers, Charles Chevalier in his ' Manuel du 



Fig. 15, 



Fig. 14. 



Micrographe ' (1839) proposed ' to place above a doublet a concave 

 achromatic lens, the distance of which could be varied at pleasure. 

 The effect of this combination is to increase the magnifying power 

 and lengthen the focus. Thus arranged, this instrument will be the 

 most powerful of all simple Microscopes, and the space available for 

 scalpels, needles, &c., will be much greater than with a doublet alone. 

 The further the concave lens is removed from the latter, the greater 

 will be the amplification.' This combination, applied to lenses for 

 examining the eye and skin, allows the use of doublets which leave 



* Robin, C, ' Traite du Microscope et des Injections,' 2nd ed. (Svo, Paris. 

 1877), pp. 33-4 (1 fig.). 



