SKIN, MUCOUS AND SEROUS MEMBRANES. 



667 



Plates and rings of bones, and atheromatous deposits, contain- 

 ing oil-globules, granules, and crystals of cholesterine, are all 



FiQ. 376. 



sometimes found in the larger ves- 

 sels. (Fig. 376, 377.) 



Lymphatics. — It is very difficult to 

 examine the minute structure of the 

 lymphatic glands. The fluid which 

 exudes from a freshly cut surface 

 may be examined by mixing it with 

 water and placing it between two 

 pieces of glass. It is very important 

 to distinguish between lymphatic cells on the one hand, and pus- 

 globules and white corpuscles of the blood on the other ; not 

 only as regards their appearance, but also in relation to the dif- 

 ferent .effects produced by reagents. 



EXAMINATION OF THE SKIN, MUCOUS AND SEROUS 

 MEMBRANES, ETC. 



Shin. — A good view of all the structures composing the skin 

 may be obtained by making a vertical section. In this manner 

 the relation of the various layers, the arrangement of the hair- 

 bulbs and sebaceous follicles, and the position and course of the 

 sweat-ducts, may all be demonstrated. 



The following method of procedure is recorded by Dr. Beale, 

 as quoted from Giraldis by Kblliker : 



" The skin should be perfectly fresh, and a piece about two 

 inches square, or rather less, is to be stretched with the outer 

 surface downwards upon a thick deal board by means of numerous 

 pins. If the sudoriferous glands are to be included in the pre- 

 paration care must be taken to leave sufficient of the cellular 

 tissue adhering to the skin. The piece of skin is allowed to dry 

 by exposure to the air. Several small pieces taken from various 

 parts of the body may be pinned out on the same board, care 

 being taken to attach a label to each. Specimens may be taken 

 from the scalp, eyelids, chin, mamma, axilla, arm or leg, palm of 

 the hand, tips of the fingers, sci'otum, and sole of the foot. With 

 these, the varying thickness of the epidermis and other peculiari- 

 ties in the different regions may be demonstrated. 



