NEW FORM OF SECTION-CUTTING BIACHINE. 271 



screw (b). Upon this table the hard material is firmly fixed by a 

 screw clamp (c) ; a fine saw (d), firmly guided hy the supports [e,\ and 

 springs (f) makes the first cut. The table (a) is then moved forward 

 the requisite distance by means of the screw (b), the saw again put in 

 action, and a section is made equally thin throughout, and ready for 

 examination by the microscope. 



You will now also understand wliy my machine differs from all 

 others, I having started originally from a very simple idea, and 

 only made additions as the apparent necessity arose, and the result 

 was, that the more complex it became, the less necessity was there 

 for skill, and the greater the saving of time and labour to the 

 operator. There are still several points to which I must call your 

 arttention, connected as they are with the careful working of the 

 machine under different circumstances and on different materials. 

 Of these I shall take muscle and brain matter as representing soft 

 material, and bone and teeth as representing hard material. For 

 these two different consistencies the two opposite sides of the 

 machine have been separately adapted, and I shall commence with 

 the latter, i.e., the hard substance — anything, in fact, which steel 

 will cut. Take for example a tooth (not the enamel part). 



Now, if we consult the latest works on histology, say those of 

 Beale and Kolliker, we are informed that to prepare a section of 

 a tooth, we first break off a piece as small as is convenient, and fix 

 it by means of some hard cement, which will hold it firmly em- 

 bedded while one side is being ground down perfectly level and 

 polished on a lapidary's wheel. This finished side is next to be 

 placed, in its turn, upon a piece of plate-glass, by means of cement, 

 and the other side is then ground down until the remainder is so 

 thin as to be transparent and polished ; it is then to be taken off, 

 cleaned, and mounted, and I leave you to consider the time, the 

 skill, and the labour required to make one section according to that 

 formula. 



Now, with my machine, you sitiiply lay the tooth on the brass 

 table under the saw, tighten it down, place the saw in position, and 

 work it backwards and forwards till the first cut is made ; all this 

 may occupy five minutes. After this you may make a dozen 

 sections, occupying two or three minutes with each section ; these 

 come off polished and clean, and ready for mounting. Moreover, 

 no practice or skill is required ; any tyro can make a good section 

 on at most his second attempt, for neither saw nor article sawn cim 



JouEN. Q. M. C, No. 27. s 



