26G J. FULLAGEii ON DEVELOPMENT OF HTjdrct Vulgaris. 



D, appearance of envelope before the rupture of the egg indicated at E. 



F, part of the Htjdra protruding from the egg. 



G, indication of tentacles. 

 H, further development of tentacles. 



Full development of young Hydra, fixed to the inside of shell at I. 

 Hydra, K, sperm cells, of which there are three ; L, discharge of 

 spermatozoa; M, ovum about to leave the body. 



On a new form of Section-cutting Machine for the 

 Microscope. 



By George Hoggan, Esq., M.B. and CM. 

 {Eead May 22ncl, 1874.) 



Having been requested by your President to exhibit the Section- 

 cutter invented by me, and to show tlie manner of making sections 

 of bard and soft material by it to your Society, I willingly comply, 

 not with the idea of showing you anything very ingenious, but 

 simply as a means of facilitating histological research ; and at 

 the present day I know none of its departments in which more 

 valuable aid can be rendered than in the contriving of some plan 

 whereby large sections of different materials may be cut easily, 

 quickly, and correctly. These three words embody the design 

 aimed at in this machine, and they ought to form the three heads 

 of any discourse on section-cutting. 



At the same time I shall not confine myself to a mere descrip- 

 tion of my machine, but give also such hints as may prove useful in 

 section-cutting generally, hints which I m\ self have discovered and 

 proved by long experience ; but although the inventor of a section- 

 cutter of an entirely new design, I must warn you against the 

 supposition that section-cutting is the only thing needful in 

 histology ; on the contrary, most of the histology of isolated 

 structures may be investigated by teazing with needles or by 

 cutting small pieces by hand, but when the general relation of 

 histological elements in any organ, or the origin of morbid 

 elements (as in a tumour), is to be investigated, then it is only by 

 a complete section of the whole mass that a correct idea can be 

 arrived at. 



To effect the section of such lar<T[e masses I insist on the 



