THE MICROSCOPE IN PATHOLOGY. 229 



to the staining fluid, etc., not with a camel's hair brush, 

 but with a little slip of tin, copper, etc., with a bent and 

 perforated end, making a sort of lifter or flat spoon. In 

 making sections, either by hand or with the section-cut- 

 ter, the razor or knife must be kept always sharp, and 

 drawn from heel to point so as to cut with a single stroke 

 the thinnest possible slice. 



THE APPEARANCE OF TISSUES AFTER DEATH. 



Formation and decomposition, or progression and retro- 

 gression, coexist in most morbid structures, so that it is 

 necessary for the student not only to be familiar with 

 normal histology, but also with the products of decay and 

 death and the varied appearances in disease. 



The death of the individual parts of the organism is 

 called necrosis, mortification, or gangrene. Various changes 

 follow it, depending chiefly on moisture, producing dry or 

 moist gangrene. 



Necrosis depends on the cessation of the nutritive pro 

 cess from abolition of the normal supply of blood, or from 

 mechanical or chemical violence. 



Living tissues bathed in suitable fluids dissolve albumi- 

 nates and their derivatives, but when life departs they no 

 longer withstand solution themselves. 



1. Protoplasm. It has been shown, page 118, that the 

 term bioplasm has been appropriated to elementary or 

 germinal structure during life, and at page 188 we re- 

 garded the leucocytes, or white corpuscles of the blood, 

 chyle, etc., as simply bioplasts. After death, or in order 

 to designate their physical constitution, the most suitable 

 term for them is protoplasm. In necrosis this colorless 

 protoplasm dissolves after slightly swelling, and entirely 

 disappears. 



2. Blood. Decomposes very rapidly. The coloring 

 matter leaves the red corpuscles and is diffused through 



