136 MAN, — THE ANIMAL 



gen. While this is the most conspicuous aspect of 

 this disease caused by the poison of the rattle- 

 snake, it is only a part of the story. The main 

 point to be emphasized in this connection is that 

 a definite poison introduced into the blood pro- 

 duced specific results. 



The question is often raised why it is safe to 

 suck the wound and swallow the poison thus re- 

 moved. The explanation is very simple. The 

 poison of the rattlesnake is made up of a sub- 

 stance known as protein, similar to the protein 

 of our food. When a protein is taken into the 

 stomach, it is digested and this is what happens to 

 the poison of the rattlesnake. If the white of a 

 hen's egg is injected directly into the blood of man, 

 it acts as a violent poison, although when taken 

 into the stomach it is one of the best of foods. 



The following illustration presents a similar 

 phase of the problem — how organisms cause 

 disease : There is one group of plants known by 

 the general term of Fungi. To this group belong 

 bread mould, bacteria, and mushrooms. The 

 common appHcation of the name toadstool or 

 mushroom has no scientific meaning. The plants 

 to which these general terms are applied have 

 specific scientific names which enable the expert to 

 recognize them. There are no common tests by 

 means of which those that are poisonous and those 

 that are not can be distinguished. It is necessary 



