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PATHOGENIC BACTERIA. 



FIG. 76. Tetanus bottle. . 



a couple of inches long. Connected with this glass 

 tube, by means of a short piece of rubber tubing, is 



the bulb of a broken pipette, 

 the other end of which is 

 plugged with cotton (Fig. 76). 

 When the steam sterilization 

 takes place the expanding fluid 

 ascends -to the reservoir repre- 

 sented by the pipette bulb, de- 

 scending again as the fluid cools. 

 When the sterilization is com- 

 pleted the reservoir is detached, 

 the inoculation made by passing 

 a very fine pipette into the bottle, 

 the projecting glass tube drawn 

 out to a fine tube, and the bottle 

 stood in hot water until the ex- 

 panding fluid ascends to the apex 

 of the pointed glass tube. The 

 tube is now sealed in a flame and the bottle and its con- 

 tents allowed to cool. In cooling the retracting fluid 

 leaves a vacuum which at once draws up any minute 

 bubbles of air remaining, and allows the tetanus bacillus 

 to grow in a condition of very fair anaerobiosis. 



Tetanus bacilli exist in nature as widely distributed 

 saprophytes. They are quite common in the soil, and 

 the fact that they are most plentiful in manured ground 

 has suggested that they originate in the intestines of 

 horses and reach the earth from their excrement. Le 

 Dentu has, however, shown that the tetanus bacillus is 

 a common organism in New Hebrides, where there are no 

 horses. In these islands the natives poison their arrows 

 by dipping them into a clay rich in tetanus bacteria. 



The work of Kitasato has given us a very exact 

 knowledge of the tetanus bacillus and completely estab- 

 lislics its specific nature. 



The organisms generally enter the animal body through 

 a wound caused by some implement which has been in 



