TRANSACTIONS OF THE ROYAL MICROSCOPICAL 



SOCIETY. 



UBRARY 

 NEW YORK 



BOTANICAL 



GARDEN 



On Microscopic Sublimates ; and especially on the Subli- 

 mates of the Alkaloids. By William A. Guy, M.B., 

 F.R.C.P., F.R.S., Professor of Forensic Medicine, King's 

 College, &c. &c. 



(Read Oct. 9, 1867.) 



The paper wliich I submit to the Society this evening has 

 for its object to extend and strengthen the union which 

 already exists between micro-chemistry and the microscope. 

 I wish to show that, by a very simple chemical operation, we 

 may obtain a vast number of new microscopic objects ; and 

 that by the application to them of a few chemical reagents, 

 of which the immediate and remote eflPects must also be 

 studied under the microscope, the number of such objects 

 may be almost indefinitely increased. Let me add that this 

 subject, if I am not greatly mistaken, will, be found to com- 

 mend itself to the Society by combining in an unusual degree 

 the claims of novelty, largeness of scope, and practical 

 utility. I will offer a few remarks under these three heads. 



1. Novelty. — The history of this subject dates from the 

 year 1858, when I proposed to substitute for the reduction- 

 tube in common use a short specimen tube, closed above by 

 a flat disk of glass, and, in certain cases, a slab of white por- 

 celain, a ring of metal or glass, and the same glass disk, 

 g^he heat of a spirit lamp was to be applied to the tube or 

 ^ab, and the vapour of the object vmder examination was to 

 ^e received on the disk. This simple method was first 

 ^)plied to arsenious acid and the metal arsenic, and bore as 

 CJts first fruits the analysis of the arsenic crust, and the dis- 

 bgpvery that metallic arsenic is deposited from its vapour in 

 ■^Q form of globules ; and that the crystals of arsenious acid 

 *^sume forms not previously described, among which the 

 tetrahedron is not to be found. The new method was re- 

 commended, and these facts recorded, in ' Beale^s Archives of 

 vol. XVI. a 



