444 MANIPULATION. 



by thin sections made with the scalpel. The above described 

 method of examining a mucous membrane, although applied 

 to the stomach, wiU be found to answer equally well for that 

 of all other parts, not only of the alimentary canal, but all 

 tracts except those in which the epithelium is so abundant, as 

 to form a perfect layer of cuticle ; in aU these latter cases, it 

 must be needless to mention, that in order to examine the 

 mucous surface, the layer of cuticle must have first been 

 removed; this cannot often be done in the fresh state, 

 the operation of maceration must then be had recourse to for 

 the purpose. If the surface be villous, and have been kept 

 in spirit for some time, it should be pinned out and well 

 washed, either by a stream of water, allowed to run on it, or 

 by a syringe ; if the preparation be then allowed to remain in 

 water for a short time, all the villi wiU float up, and their 

 shape be ascertained. In modem times the art of injection, 

 which, in this country, had for a long period been neglected, 

 began to be again revived, with the employment of the 

 achromatic microscope ; and, by its agency, within the last 

 few years, numerous most interesting discoveries have been 

 made, especially since the invention of thin glass, and the 

 mounting of objects In cells as first practised by Mr. Goadby, 

 have been adopted. The different methods of injecting will 

 be given in a subsequent work, in this place it will be merely 

 necessary to enumerate some of the objects of the greatest 

 interest that may be selected from the mucous membranes, 

 either injected or not, that may serve as a guide to the under- 

 standing of the different elements of which it is composed. 

 In addition to the names of preparers of microscopic objects 

 mentioned at page 399, the author would beg here to intro- 

 duce that of Mr. Hett, of No. 24, Bridge Street, Southwark, 

 whose preparations in this department are so well and 

 deservedly known. 



Epithelium. Scaly — Mesentery, Mouse, 



Scaly — Skia of Newt, — Mouth, Human, 



— Web of Frog's foot, — Cuticle, 



— Mesentery, Kabbit, — Cornea of eye. 



