THE NERVOUS SYSTEM 



37i 



is healing. Should infection have taken place, if the wound is 

 closely examined, it will be observed to have a peculiar dusky 

 copper colour, and not that bright strawberry-red seen in healthy 

 granulations. The organism, or bacillus, supposed to cause the 

 malady is said to confine itself to the wound and its immediate 

 surroundings, and it excretes or manufactures a material which, 

 being absorbed into the tissues, acts upon the nervous structures 



Fig. 15. — Tetanus. 



and produces the disease. With reference to these disease-producing 

 germs, spores, microbes or bacilli — in other words, the seeds of the 

 disease — they have, for some time past, been experimented with by 

 a number of microscopists in the laboratory, aud there cultivated, 

 grown, and tested with suitable food (medium), air, moisture, and 

 temperature. Their specific nature has been determined by inocula- 

 tion, according to the particular disease to which they belong ; but 

 when such a disease appears in the farmyard, or in the sheep-fold, 

 there seems to be something else wanting besides the conditions 



