THE SALIVARY GLANDS. 209 



The injected specimens are much improved by slightly 

 staining them with logwood. 



Preparation 9. Palate and tonsils. The soft 

 palate and the tonsils may be hardened in the same 

 way as the tongue, or, preferable, by immersion for 

 a week in per cent, chromic acid solution, and sub- 

 sequent placing in spirit. The sections are stained 

 with logwood and mounted in dammar. 



THE SALIVARY GLANDS. 



Preparation 10. These organs are prepared by 

 placing small pieces of them as soon after death as 

 possible in a mixture of spirit and J per cent, chromic 

 acid solution, equal parts of each. After two or 

 three days they are transferred to spirit, and in a 

 day or two more will be ready to cut. They may 

 also be prepared by merely being placed in strong 

 spirit for three or four days. The embedding, stain- 

 ing with logwood and mounting, are effected in the 

 ordinary manner, the chief difficulty being met with 

 in the fact that, owing to the loose way in which 

 the lobules are held together by the intermediate 

 connective tissue, the sections are very apt to become 

 broken up by the agitation which ensues from the 

 mixing of the fluids, particularly when they are 

 transferred from spirit to water or to a watery solu- 

 tion of logwood. An alcoholic logwood (Kleinen- 

 berg's) may, however, be used, and in any case it will 

 be found that the small pieces exhibit all the details 

 of structure quite as well as larger ones ; thin sec- 

 tions which have thus become broken up need not 

 therefore be rejected. 



Preparation 11. The difference in the structure of 

 the salivary glands previous and subsequent to the state 

 of secretory activity is best studied in the submaxillary 

 of the dog, the animal being killed in the one case after 

 some hours' fasting, in the other a short time after food. 

 The glands are hardened and sections are prepared in 

 the manner above described, and the differences in the 



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