266 BOARD OF AGRICULTURE. 



subject, namely, how to protect ourselves from these potent 

 enemies. 



Among the many diseases men and animals are subject to 

 there is one known as anthrax, one of the most terrible and 

 rapidly fiital of diseases. For example, a little pimple 

 appears on some part of the face or neck, caused by the 

 bill of an insect that has been feeding on the body of an 

 animal dead of the disease ; in a very short time it begins 

 to swell and becomes painful ; in a few hours the vicinity of 

 this pimple becomes hard and of a bluish black color and 

 perhaps the whole head and neck are swollen, blackish spots 

 appear on other parts of the body, the pulse becomes quick and 

 feeble, the breathing labored, the vital powers fail rapidly 

 and at the end of forty-eight or sixty hours death closes 

 the scene. It was known more than thirty years ago that 

 the blood of one suffering from this disease was filled with 

 these minute bodies, such as you see upon the screen (pho- 

 tograph shown) ; but it was supposed that these were rather 

 the result of the disease than the cause of it, until a few 

 years ago an observer introduced some of these germs from 

 a body dead of this disease into the body of a healthy 

 animal, and in a few hours this animal sickened and died of 

 this disease. This experiment was tried a great many times 

 and always with the same result. "While such experiments 

 indicated perhaps that these bacteria were the cause of the 

 disease, they by no means proved it, for, in taking some of 

 these germs from the blood of a body dead of the disease 

 with which to inoculate the animal, some of the blood itself 

 must have been taken, and that, or some other poison it 

 might contain, may have produced the disease in the animals 

 experimented upon. 



Later a great discovery was made, and one that has 

 enabled us to solve the question of the relations of these bac- 

 teria to contagious disease ; that discovery was, that these 

 germs could be cultivated and grow outside the body, some 

 requiring one set of conditions, and some another, for their 

 development. For example, nearly all of them will grow 

 in solutions of meat juice, others will only grow in blood 

 serum, while still others require vegetable substances for 

 their development. 



