86 THE MICROSCOPE. 



sharpness of contour, and often deeply pigmented. The nuclei 

 have often been absent and the cells filled instead with innumerable 

 pigment granules. The gray matter in the floor of the fourth ven- 

 tricle has presented a similar appearance, and the cells of the facial 

 and hypoglossal nuclei have rarely been found normal. 



Dr. Munson has the following apparatus: The microscope 

 stand consists of a broad tripod base from which rise two columns, 

 carrying the trunnious between which the instrument swings, and 

 can be inclined at any angle. The whole can also be rotated upon 

 its central axis. The mechanical stage is four inches square, and 

 has a rectangular motion to the extent of one inch in each direc- 

 tion. The bar carrying the plane and concave reflectors swings 

 around a centre which lies in the plane of the object, and allows the 

 reflectors to be swung above the stage for illuminating opaque 

 objects. The sub-stage carries the polarizing prism, achromatic 

 condenser, and other accessories, and is arranged for accurate cen- 

 tering and up and down motion, by rack and pinion. The optical 

 tube is i% inch in diameter and is graduated and slides up and 

 down by rack and pinion. The fine adjustment is by lever and 

 screw. There are four eye-pieces; No. 2 being supplied with an 

 indicator, No. 3 being solid, and No. 4 being orthoscopic and pro- 

 vided with micrometer. The objectives are 3 in., \}/z in., ~/i in., % 

 in. with Lieberkuhn, £ inch adjustable, dry, ^ immersion,^ immer- 

 sion. There is also a polariscope, wide-angled achromatic con- 

 denser, a stage micrometer and a double oblique nose piece. The 

 price complete was $500. — • W. W. Munson, M. D., in ''Report of 

 Eastern Asylum" Pontine, Mien. 



Microscopic Analysis of the Structure of Iron and 

 Steel. — After briefly reviewing the work of A. Martens, of Berlin, 

 and Dr. H. C. Sorby, of Sheffield, in this field of research, Mr. 

 Bayles considered the methods of preparing specimens for micro- 

 scopic study which in practice he had found to give the best results, 

 and continued: The first step to be taken in practical microscopy 

 is the training of I -to observe what may be seen without the 



aid of a lens. This is accomplished by the patient examination of 

 characteristic features, and noting similiarities and differences. 

 After the naked eve has become familiarized with all it can see, the 

 student should continue his investigations assisted by a hand-lens 



