20 CUTTING AND MOUNTING TISSUES. 



over a flame until the odor of the clove oil has disappeared. Care 

 must, however, be taken not to shrivel the tissue by overheating it. 



A better method of fastening the sections, is to albumenize the 

 slide by soaking it a short time in a mixture of egg albumen 1 

 part, water 200 parts, and then allowing the slide to drain until 

 dry. A number should be treated at one time and kept on hand 

 until desired for use. With these slides, by warming the sections 

 until the paraffine melts, the preparation will flatten out and 

 adhere with great tenacity to the albumenized surface. The 

 albumen will not be effected by staining. 



After the sections are fastened, the slide is placed in tur- 

 pentine, or better, in xylol to dissolve away the paraffine. This 

 will usually be accomplished in 15 to 20 minutes, when the object 

 is washed with water and is ready for staining. The stain to be 

 used and the method of applying it depends largely on the nature 

 of the tissue and the part one desires to bring out. For general 

 studies haematoxylin works well and with eosin makes a good 

 double stain. If the haematoxylin is used, the slide need be left in it 

 but a few minutes, when it is removed and washed thoroughly with 

 water to take out the surplus stain, dehydrated with 95 per cent, 

 alcohol, cleared for a few minutes in clearing mixture, and mounted 

 in balsam. If the tissue is to be stained in toto, before imbedding, 

 Mohl recommends that it be taken from the 60 per cent, alcohol, 

 while being hardened, and placed for 24 hours in a solution of 

 alum carmine, after which the hardening can continue. With this 

 treatment, when sectioned, it is only necessai'y that the paraffine be 

 dissolved away, the tissue cleared with a clearing agent, and 

 mounted in balsam. With haematoxylin or alum carmine the cell 

 wall stains well and the nuclei show very clearly. In double stain- 

 ing, if eosin is applied, the sections need be left in it but 20-30 

 seconds. If glycerin jelly is to be used as a mounting medium, the 

 sections can be mounted directly after washing off the surplus 

 stain with water. 



During the Sectioning it may happen that some of the parts of 

 the section will loosen as they are being cut away. In this case 

 they may be held together with collodion applied in a 1 per cent, 

 solution with a camel's hair brush. This is painted over the tissue 

 just before the section is cut, it dries quickly and hold all the parts 



