238 THE AMERICAN MONTHLY [Aug, 



larly to the surface of the organ ; mount in balsam after 

 staining the nuclei by hgematoxylin. 



Gall Bladder. — To see the epithelium, open a rabbit's 

 gall bladder and put it in an iodised serum for 24 hours ; 

 scrape the internal surface and spread the result in a 

 drop of picro-carmine, and run glycerine under the 

 cover after staining. 



The muscular fibres should be prepared as described 

 for the bladder of the frog. 



The nerve plexus. — Remove the bile and inject fresh 

 filtered lemon juice. Put the bladder in a few cc. of 

 lemon juice and leave it for five or six minutes. Wash 

 again and reduce the gold in the i formic acid. Examine 

 pieces of the bladder in glycerine after brushing away 

 the epithelium. 



PANCREAS. 



Study by the method described for the salivary 

 glands. 



To dissociate the cells, macerate fragments in I alco- 

 hol. Section after fixation by alcohol, osmic acid or 

 a m m on ia bichromate. 



Complete the study by using Gribbes' method, which 

 gives beautiful differentiation of the cells. Sections 

 made after the use of ammonia bichromate are stained 

 for ten minutes in the following solution : distilled 

 water, 100 grms. ; vesuvine, 5. Wash rapidly in water 

 and stain by : distilled water, 100 grms. ; indigo-car- 

 mine, 5 grms. When colored a deep blue, wash in water 

 and mount in balsam. 



RESPIRATORY APPARATUS. 



Nasal mucous luemhrane. — Take a portion from the 



upper region (olfactory region) and another from the 

 lower part. 



To dissociate the epithelial cells. — Put a piece of the 



