100 METHODS. 



PART II. 



PREPARATION OF THE COMPOUND TISSUES. 



CHAPTER VI. 

 METHODS. 



THE methods of examining tissues in the fresh state, with 

 or without the addition of reagents, and of isolating the ele- 

 ments by the process of teasing with needles, have been fully 

 described in the First Part. We have also seen that, in trans- 

 parent structures, particularly membranes, the anatomical 

 relations of the elements may be studied, either by observing 

 them in the natural condition, or after preparation with the 

 solution of chloride of gold, or with that of nitrate of silver. 

 For the investigation of the compact tissues, other modes of 

 preparation are necessary, in order to bring them into such a 

 condition that fine sections can be made of them. It is the 

 purpose of this chapter to describe the method by which this 

 is accomplished. 



Preparation of Sections of Fresh Tissues. There 

 are a few organs or parts of organs which possess such a con- 

 sistence that it is possible, without preparation, to make micro- 

 scopical sections of them ; such as cartilage, some tumors, 

 skin, hypertrophied lymphatic glands, prostate gland, kidney, 

 liver, and under certain circumstances involuntary muscle. 

 Sections of these tissues serve either for the study of the con- 

 dition of the elements, or the action of reagents ; or are made 

 with a view of treating them with gold or silver. They are, 

 however, mainly useful as facilitating the preparation of the 

 individual elements by the process of teasing. For this pur- 

 pose the section may be either used in the fresh state with 

 indifferent liquids, or after maceration in iodized serum, Miil- 

 ler's fluid, or one per cent, solution of bichromate of potash. 



For the study of the anatomical relation of fresh tissues, 

 other methods must be used. The simplest plan is to take thp 

 object in the hand, and use a sharp section knife. It is some- 

 times recommended to fix the tissue between elder pith or 



