io8 



PARAFFIN AND COLLODION SECTIONS. 



65. These may be carried on (a) as loose sections, or (b) 

 fastened to the slide. 



(a) Sections not fastened to the slide may be carried on in 

 watch glasses, or larger glass vessels if there are many of them, the 

 sections either being transferred from vessel to vessel by means of 

 forceps or a section-lifter, or the fluid decanted, care being taken 

 not to pour off the sections, and the succeeding medium added. 

 Single sections may best be carried on upon the slide, which must 

 be kept horizontal. When the fluid is to be changed place a brush 

 or needle gently on one corner of the specimen and pour off the 

 liquid, if necessary first absorbing most of it by means of a pipette ; 

 in this way the section may be retained on the slide. 



(b) Fastening the Sections to the slide. This is of great 

 advantage in carrying the sections on through the different steps. 

 With serial sections it becomes an absolute necessity. Different 

 methods are employed for collodion and for paraffin sections. 



66. (i) Collodion sections. If the sections are trans- 

 ferred to the slide from clarifier, absorb the oil thoroughly by 

 placing over the section some absorbent paper and pressing it down 

 gently and firmly, repeating the operation several times with fresh 

 paper. After the oil is well absorbed, with a pipette drop upon the 

 section enough ether-alcohol to moisten it (1-2 drops). This soft- 

 ens the collodion and fastens the section to the slide. Allow the 

 ether-alcohol to evaporate until the collodion has again set and the 

 surface of the section looks dull or glazed, and then place it in ajar 

 of benzin. Take care that the specimen does not dry. 



If the sections are in series, it is better to put the ether-alcohol 

 on one end of the slide and let it run quickly over the sections and 

 drain from the other end of the slide, repeating the operation two 

 or three times. If it is found that the sections float off of the slide 

 in the process of staining, their adhesion may be insured by using 

 albumenized slides or removing the slides from the alcohol ( 69) 

 and again treating with ether-alcohol. 



67. (2) Paraffin sections. If the sections are unwrinkled, 

 or with a few wrinkles that may be easily " ironed out," fasten them 

 to the slide with (a) albumin fixative and y% collodion, or (o) 



