48 ELEMENTS OF APPLIED MICROSCOPY. 
Once well imbedded, a cube of solid paraffin contain- 
ing the object is cut out and fixed in a microtome, such 
as is illustrated in Fig. 25. Several good instruments are 
on the market, of which the Thoma and the Minot- 
Blake types may be mentioned. In any case the knife 
and object are firmly held in supports moving at right 
angles to each other; and one or other of the supports is 
Fic. 25.—THoma Microtome. (After Carpenter-Dallinger.) 
so arranged that by some mechanical device it can be 
shifted by any desired amount between each excursion, 
according to the thickness of the sections desired. If the 
surrounding temperature be right, the successive sections 
of paraffin will adhere by their edges, forming a long 
ribbon. In such a ribbon each serial section represents 
one plane in the original specimen; and the whole object 
may thus be unrolled as it were upon the slide, each 
structure being easily traced from section to section. 
Minute sections obviously cannot be handled by them- 
selves. It is desirable, therefore, to affix them to the 
