106 THE MICROSCOPIST. 



will speedily stop. The motion and structure of the cilia is 

 sometimes better observed after the lapse of some hours, as the 

 movement will then have become sluggish. 



Sometimes the ciliary movement may be witnessed on 

 epithelial scales found in the mucus taken from the nasal pas- 

 sages during a slight catarrh. 



INJECTED PREPARATIONS. For the mode of making these 

 preparations, the reader will refer to the chapter on Minute 

 Injections. 



There can be no doubt but that the blood is, par excellence, 

 the vital fluid. From it is derived the material for the develop- 

 ment of each part of the organization ; nerve as well as muscle, 

 bone, tendon, &c. Even unnatural and morbid growths must 

 have their origin in some alteration in this all-pervading, all- 

 sustaining fluid. " The life thereof is the blood thereof." 



The capillary vessels of the body form the vehicle of vital 

 distribution and stimulus. By them is conveyed the nutrition 

 of all the tissues ; and through them all foreign substances are 

 extracted, and the blood thus rendered pure and vital. By 

 endosmotic action through their thin coats in the lungs, oxy- 

 gen unites with the carbon, and probably the iron of the blood, 

 and carbonic acid gas is expelled; and from their peculiar ar- 

 rangement in the kidney, lobules of the liver, &c., effete mat- 

 ters are strained, as it were, from the circulation, and carried 

 off. 



But there is another function, of equal, if not superior, im- 

 portance with those just mentioned, which, in the judgment of 

 the author of this work, the capillaries are destined to subserve. 

 They are, doubtless, the cause, perhaps the sole cause, of the 

 difference in the sensations experienced in the various organs 

 and tissues of the animal frame, under the stimulus of the 

 varied excitants to which the organization is subject in health 

 and disease. The nervous cords may transmit impressions to 



