VII] SECTION CUTTING AND IMBEDDING 51 



frame straight forward again, and so on. In a short 

 time, sections of the tissue will be obtained. With a 

 small brush moistened with water remove each section, 

 as it is obtained, from the razor, and float it off in a 

 dish of water. A number of sections may be cut, and 

 these removed together from the razor, but the sections 

 are apt to become entangled and they are generally 

 less perfect than the sections which are removed sepa- 

 rately as they are cut. 



After cutting some sections, of a thickness corre- 

 sponding to Jth of a revolution of the front screw, cut 

 others, turning the screw less than Jth between each 

 section, and note the smallest angle through which 

 the screw can be turned, complete sections still being 

 obtained. 



Stain and mount the sections. (See Lesson v.) 

 It must be remembered that the gum unless dissolved 

 out of the sections will form a granular precipitate in 

 them when they are treated with strong alcohol. 



After the sections are cut, carefully clean the razor 

 and the plate of the microtome. 



The proper rate to carry the razor through the 

 tissue varies with the temperature of the frozen mass ; 

 when it is a few degrees only below zero, the movement 

 may be the quickest possible ; when it is frozen hard, 

 it should be carried slowly through the tissue, other- 

 wise the sections are apt to curl or break up. 



6. In cutting large sections, it is best to place on the razor a 

 number of small drops of water and to cut slowly ; the section folds 

 up on the razor. The razor (with the frame) should then be dipped 

 under water and the section floated off ; it should be taken out on a 

 glass slide and treated on the slide with 30, 50, 75 p.c. alcohol, etc. ; 



