222 PRACTICAL HISTOLOGY. 



ceeding, and when it is finished all that remains is 

 the thin serous coat and the longitudinal muscular 

 layer, to the inner side of which the nervous plexus 

 of Auerbach, the intermuscular plexus, is adherent. 

 ~No further separation is required, all that is neces- 

 sary being to float the piece of tissue on to a slide 

 with the (concave) inner surface uppermost. But 

 before applying the cover-glass the preparation is to 

 be examined with a low power, to see that the sur- 

 face of the serous membrane is free from a finely 

 granular precipitate which is apt to be deposited in 

 the acidulated water. If this is present, the piece 

 must be replaced in the water and the precipitate 

 gently brushed oft' with a soft camel-hair pencil. 

 The preparation is completed in the same way as 

 that of the submucosa. The latter shows Meissner's 

 plexus, the cords of which are much finer than those 

 of Auerbach's. In both plexuses the nervous cords 

 are stained of a violet color by the reduction of the 

 gold ; at the points of junction of the nervous cords 

 are groups of small ganglion cells, the nuclei of 

 which are hardly stained at all, and consequently 

 look clear in the midst of the darkly-stained cell- 

 bodies. The distinction between the individual 

 cells is difficult to make out. Branches may perhaps 

 he traced passing from the plexus of Auerbach 

 amongst the muscular fibre-cells : from that of 

 Meissner to the muscularis mucosoe, if this is present, 

 and perhaps also to the small bloodvessels, which are 

 particularly well seen in the preparation of the sub- 

 mucous coat. 



Preparations 5-7. Large intestine. For 

 hardening the tissue and preparing sections of the 

 large intestine the same methods are employed as for 

 the small intestine, so that it is unnecessary to re- 

 capitulate them. 



The injected large intestine is prepared, like the 

 stomach, by means of vertical and horizontal sec- 

 tions. 



The lymphatics are not easy to inject, but present 

 ' 'Acuity than those of the stomach. 



