3 o8 COLLODION METHOD \_CH.X 



After 15 minutes, or longer if convenient, put the mounted speci- 

 men into the clamp of the microtome and cut as above. 



Sometimes when the imbedded object is of sufficient size and 

 the collodion block is firm, the block itself is put into the micro- 

 tome clamp, no wood or cork holder being used. 



§458. Transferring Sections from the Knife' to the 

 Slide. — When one has cut the number of sections for one slide they 

 should be transferred to the slide as follows : Take a piece of 

 white tissue paper about 3x6 centimeters in size and lay it on the 

 knife over the sections. Pr.ess down slightly so the paper is in 

 contact with all the sections. Take hold of the paper beyond the 

 edge of the knife and gradually pull it down off the knife. 



If there is the right amount of alcohol on the knife the sections 

 adhere to the paper and move with it. This transfers the sections 

 from the knife to a piece of tissue paper. Place the tissue paper 

 with the sections down on the middle of an albumenized slide. 

 Cover with another piece of paper and press down gently. This 

 presses the sections against the slide and absorbs a part of the 

 alcohol. Take hold of one edge of the paper and lift it with a roll- 

 ing motion from the slide. The sections should stay on the slide.* 



§ 459. Fastening the Sections to the Slide. — With a 

 pipette, drop 95% alcohol on the slide of sections, then use a 

 pipette full of absolute alcohol if it is at hand. Drain most of the 

 alcohol away and add a few drops of ether-alcohol. The collodion 

 should melt and settle down closely on the slide. If the collodion 

 does not melt the dehydration was not sufficient and more alcohol 

 must be used. After the collodion has melted down upon the slide 

 let the slide remain a minute or two in the air, and then transfer 

 the slide to ajar of 67% alcohol. (Figs. 243, 251.) 



After half an hour or longer the preparation is ready to stain, 

 etc. See below for directions (§ § 461-471). 



* Various forms of paper have been used to handle the collodion sections. 

 It should be moderately strong, fine meshed and not liable to shed lint, and 

 fairly absorbent. One of the first and most successful papers recommended is 

 " closet or toilet paper." Cigarette paper is also excellent. In my own work, 

 the heavy white tissue paper has been found almost perfect for the purpose. 

 Ordinary lens paper or thin blotting paper for absorbing the alcohol or oil 

 may be used with it. 



