PATHOLOGY. 3 



otliers, wliich are finely granular, the processes or rays are sub- 

 ject to slight variations of contour. These amoeboid movements 

 of the rays, although very sluggish as compared with those of 

 young protoplasm in general, are rendered much more active by 

 subjecting the preparation to a stream of blood serum ; for which 

 purpose Professor Strieker employs the serum of the same animal 

 which has furnished the cornea." 



From the above we learn that the application of an irritant 

 produces changes similar to those which take place in a structure 

 when first removed from the influence of vitality, and that in 

 so far it simulates the first ;post mortem changes. In a vascular 

 structure the alterations of nutrition which result from the ap- 

 plication of an irritant are as described in the following pages. 



It must be borne in mind that the blood is composed of a 

 solid and a fluid portion. The fluid, liquor sanguinis, com- 

 posed of albumen, the constituents of the fibrine, water, and 

 various salts in solution ; the solid, of two kinds of corpuscles, 

 the white and the red. The red corpuscles move rapidly along 

 in the centre of the stream of blood in a small vessel ; while on 

 either side, and close to the walls of the vessel, there is a clear 

 space called the lymph space, containing liquor sanguinis and 

 a few white globules, which move much more slowly than the 

 blood in the centre of the stream. 



The fluid part of the blood is that chiefly concerned in nutri- 

 tion. It contains the nutritive elements in solution, and is 

 absorbed by the various textures. The capillaries consist of a 

 single coat of protoplasm, so that the nutritive material can 

 easily pass out of them, and nutrition is carried on entirely in 

 the tissues which fill up the spaces between the capillaries. 

 Every tissue has an inherent power of attracting and selecting 

 from the blood — which, be it remelnbered, flows slowly at the 

 side of the vessel — those constituents best suited for its nourish- 

 ment. 



From this it will be seen that the fluid part of the blood is 

 continually transuding through the walls of its vessels, for the 

 purpose of nourishing the tissues. A perversion of this, with a 

 rapid transformation of the transuded material, and an altered 

 mode of the growth of the elements of the inflamed texture, con- 

 stitute the inflammatory process. When the tissue is irritated, 

 lymph is produced in such abundance that the lymphatics are 



