CHAPTER X 



ISOLATION OF HISTOLOGICAL ELEMENTS. MINUTE 

 DISSECTIONS 



I. ISOLATION 



A. Dissociation by Means of Formaldehyde; ciliated and 

 columnar epithelium. 1. Kill a frog and secure the hinder part of 

 the roof of the mouth and the stomach. Slit open the latter. 

 Place the objects in the dissociating fluid (see reagent 10, chap, 

 i) for a day or two. 



2. Scrape the roof of the mouth after removal from the fluid 

 and mount the ciliated cells thus obtained on a slide. Similarly 

 remove some columnar epithelium from the internal surface of 

 the stomach and mount on another slide. 



3. Add a cover-glass and examine. If the cells cling together 

 in clumps, separate them by drumming gently upon the cover- 

 glass with the handle of a needle. 



4. Stain by placing a drop of picro-carmine (reagent 14, 

 chap, i) on the slide just at the edge of the cover and applying a 

 bit of filter paper to the opposite edge of the cover. The filter 

 paper absorbs the fluid from under the cover and the stain 

 replaces it. 



5. After 15 or 20 minutes replace the stain by glycerin in a 

 similar manner. 



6. If a permanent preparation is desired the cover-glass must 

 be sealed (see chap, xiii), or, after staining, the tissue must be 

 dehydrated and mounted in balsam in the usual manner. 



B. Isolation of Muscle Fibers by Maceration and Teasing. 

 1. Place small fragments of voluntary muscle, of the root of the 

 tongue, and of heart muscle of the frog into separate vials con- 

 taining MacCallum's macerating fluid (reagent 80, Appendix B). 

 After 2 days pour off the fluid, fill the vials about half full of 

 water and separate the fascicles by shaking the vial. Further 

 isolate the fibers by teasing. 



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