Method VIII - 53 



danger being that the cover is easily moved, and thus the prepa- 

 ration may be lost. The cover-glass may be sealed down with 

 any of the cements used for that purpose. 



SECTIONS. 



When it is desired to demonstrate only muscle-nerve ter- 

 minations or certain of the nerve plexuses, teased preparations 

 are amply sufificient, or even better than sections. However, 

 occasions arise when it is desired to study the more intimate 

 relations between the nerve elements and the cells upon which 

 they terminate, or when it is found that teased preparations are 

 difficult to obtain, as, for example, in case of sensory nerve 

 terminations in the skin. In these cases sections are necessary. 

 Material stained with gold chloride admits of sectioning perfectly 

 well. 



After reduction (4) and washing in distilled water (5), the 

 pieces of tissue (any tissue) may be dehydrated by passing them 

 through the increasing grades of alcohol (50 per cent., 70 per 

 cent., 95 per cent.), 1 5-20 minutes in each, up to absolute alcohol, 

 where they should remain 30-40 minutes. Use 8-10 volumes 

 of alcohol in. each case. When dehydrated, clear in xylol, 

 imbed in paraffin, section, fasten sections to, the slide, and 

 remove the paraffin, as directed in Method I, 3 to 7, inclusive 

 (p. 16). 



Or, equally well, after dehydration, the tissues may be 

 transferred to 8-10 volumes of ether-alcohol, imbedded in celloi- 

 din, hardened, sectioned, and the sections dehydrated, cleared, 

 and mounted, as directed in Method X,p. 64. 



In either case the sections are mounted in balsam (I, 16, 

 p. 19). 



A more rapid application of gold chloride for nerve termina- 

 tions may be made by placing small pieces of the fresh tissue 

 directly into 15-20 volumes of 10 per cent, formic acid (B) for 

 20-30 minutes. In this the tissue takes up water, and becomes 

 greatly swollen and somewhat translucent. 



The pieces are then placed in 6-8 volumes of the i per cent. 



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