BY DR. KLEIN. 139 



with milk (rat, kitten) or fat meat (hedgehog), and killed a few 

 hours afterwards by strangulation. The belly having been 

 opened, those parts which to the naked eye appear besl filled 

 are ligatured without delay, and placed at once (without open- 

 ing them) into Miiller's liquid, previously slightly warmed. 

 After a few days, small portions are cut out and immersed in 

 half per cent, solution of osmic acid, and then, twentj'-four 

 hours later, replaced in Miiller's liquid, or in one-tenth per 

 cent, chromic acid solution. Bits of the intestine so prepared 

 must finally be embedded in gum-mass for the preparation of 

 sections, which must be mounted in acetate of potash. In 

 sections which comprise villi,the epithelium, and the reticulum 

 and central lymphatic vessel of each villus are observed to be 

 filled with fat drops stained brown or black by the reagent. 

 When a villus is cut transversel}', it is seen that trabeculae 

 beset with blackish or dark-brown fat drops, arranged in a 

 reticulate manner, radiate from the central lymphatic outwards 

 to the epithelium. 



Bloodvessels. The arrangement of the capillary networks 

 which surround the glands, and those of the villi, must be 

 studied in injected preparations. 



Nerves. Meissner's and Auerbach's ganglia have been 

 already referred to sufficiently in Chapter V. 



Large Intestine. The methods for studying the epithe- 

 lium, the Lieberkuhnian tubes, and the solitary follicles of the 

 submucosa, the mucosa and muscular structures, are the same 

 as those used for the small intestine. The agminate follicles, 

 with their lymphatic sinuses, may be particularly well seen in 

 the vermiform appendix of the rabbit. The muscularis and 

 glands of the mucosa are best seen in the wart-like prominences 

 of the colon. Good examples of the Lieberkuhnian tubes, the 

 muscularis mucosee, and the solitary follicles, are to be obtained 

 from the dog. The ganglia of Meissner are well seen in the 

 dog and cat, and in the human foetus. 



Liver. For the study of the liver, fine sections of the fresh 

 organ may be employed. By teasing these out with needles, 

 the characters of the elements of the connective tissue, and 

 the form of the liver-cells and their nuclei, can be satisfactorily 

 made out. The arrangement of the cells in the acini can be 

 demonstrated in sections of liver of human foetus, or of the 

 smaller domestic animals, hardened in solution of bichromate 

 of potash or very dilute solution of chromic acid. The best 

 plan is to steep very small portions of liver for four or five 

 days in a large quantity of one to two per cent, solution of 

 bichromate of potash, and then for twenty-four to forty-eight 

 hours in common alcohol. The sections so obtained are 

 stained in the usual way in carmine. In such preparations 

 the beautiful regular groups or oblong tracts of liver-cells, 



