How Science Helps the Body 159 



which were stimulated in the poison-emerg- 

 ency to produce neutralizing stuff, speedily 

 fall into the habit of making it, and go on 

 doing so, often for a long time, after the 

 master of the cells has recovered and after 

 his actual necessity for it has ceased. 



Now at last we see why he cannot soon 

 suffer from the same disease again. His 

 body contains a good deal of the protective, 

 poison-neutralizing agent, and his cells go on 

 making more for a time, so that he goes about 

 poison-proof. By and by, however, the old 

 hereditary pull back to the usual routine is 

 felt, the emergency cell activity wanes, the 

 excess of protective material disappears, and 

 the acquired immunity passes away. So 

 the hero of this dramatic story of disease 

 takes his place again among ordinary mortals. 



Now in scientific speech certain poisons are 

 known as toxins. And so this cell-made 

 emergency stuff, which robs the toxins of 

 their power, is known as antitoxin. Anti- 

 toxins are effective only against the special 

 poisons which inspire the cells to their pro- 

 duction that is, they are specific. An anti- 



