STUDY OF COVER-SLIPS AND SECTIONS. 223 



deep down through the substance of the kidney as a 

 yellow, wedge-shaped mass, the base of the wedge being 

 at the surface of the organ. 



It is very rare that these abscesses — for abscesses these 

 yellow points are, as we shall see when we come to 

 study them more closely — are found either in the liver, 

 spleen, or brain ; their usual location being, as said, in 

 the kidney, mj^ocardium, and voluntary muscles. 



These minute abscesses contain a dry, cheesy, necrotic 

 centre, in which the staphylococci are present in large 

 numbers, as may be seen upon cover-slips prepared 

 from them. They may also be obtained in pure culture 

 from these suppurating foci. 



Preserve in Miiller's fluid and in alcohol duplicate 

 bits of all the tissue in which the abscesses are located. 



When these tissues are hard enough to cut, sections 

 should be made through the abscess-points, and the 

 histological changes carefully studied. 



Microscopic Study of Cover-slips and Sections. 

 — In cover-slip preparations this organism stains readily 

 with the ordinary dyes. 



In tissues, however, it is best to employ some method 

 by means of which contrast stains may be employed 

 and the location and grouping of the organisms in the 

 tissues rendered more conspicuous. 



When stained, sections of tissues containing these 

 small abscesses present the following appearances : 



To the naked eye will be seen here and there in the 

 section, if the abscesses are very numerous, small, darkly 

 stained areas which range in size from that of a pin- 

 point up to those having a diameter of from 1 to 2 mm. 

 These points, when in the kidney, may be round or oval 

 in outline, or may appear wedge-shaped, with the base 



