io 9 



albumin fixative and heat ; if the sections are wrinkled, they may 

 be extended and the wrinkles removed by the method given be- 

 low (<r). 



(a) Albumin fixative and ^ % collodion. Place upon the 

 slide a small drop of albumin fixative, spreading it out with a clean 

 finger into a very thin, even layer. Place the paraffin section in 

 position upon the slide and with a clean finger, press the section 

 into the albumin fixative, beginning at one edge of the section and 

 by a rolling motion of the finger, ironing out any wrinkles there may 

 be. With a camel's hair brush and by a single sweep, spread over 

 the section a thin coating of y^% collodion. Allow it to dry in the 

 air for a minute or so and then place the slide in a jar of benzin. Be 

 sure that the y% collodion in the bottle has not thickened, and 

 spread as little over the section as possible, otherwise a much longer 

 time in the benzin will be necessary. 



(b) Albumin fixative and heat. The employment of y\% col- 

 lodion causes the benzin to dissolve out the paraffin from the sections 

 slowly, and the collodion also stains intensely with certain dyes, 

 such as safranin, gentian violet, methylgreen, methylene blue, iron 

 hematoxyline, etc. When these stains are to be used, fasten to the 

 slide in the manner following : Prepare the slide with albumin fixa- 

 tive and press the section to the slide as directed above. Look upon 

 the reverse side of the slide to see if the section really adheres to the 

 albumen fixative, as in some cases it does not. Heat the slide gently 

 and slowly over a small flame until the paraffin melts and begins to 

 run away from the specimen. Keep the paraffin just melted for a 

 minute or so, and then transfer to the benzin. A minute or two in 

 benzin will suffice. Should the paraffin section not adhere to the 

 albumin fixative when well pressed down, it can in many cases be 

 made to do so by briskly rubbing the reverse side of the slide with a 

 woolen or silk cloth. 



(c) Extending sections with warm water. If the sections are 

 wrinkled, as they often are, remove the wrinkles by extending the 

 sections on warm water, as follow T s : Place the sections upon a slide 

 prepared with a very thin, even layer or film of albumin fixative 

 ( 67, ), and add at the side enough water to float them. Warm 

 the slide carefully and slowly over a small flame until they begin to. 

 straighten out. Do not let the water become warm enough to melt 



