HOW THE BODY FIGHTS DISEASE 



and mercury or iodide, for syphilis. That was all. 

 If in ten or twenty years the new medicine has 

 found five or six more, it has not done badly. 



And it is only within the last forty years that any 

 mortal man has had the least idea of the nature of 

 disease. It is curious to think that not even the 

 wisest of men before this had so much as a sus- 

 picion of the truth. In many other lines of physi- 

 cal inquiry there were shrewd guesses that turned 

 out not far from the mark. But when the invisible 

 air, the crystal spring, the unsuspected dust, were 

 shown swarming, teeming, feculent with microbes, 

 some benign, some indifferent, some of them ma- 

 lignant, it was as if the walls of the unseen had 

 dropped. 



Let us, then, be patient. The new methods prom- 

 ise much ; moreover, they are the sole promise. In 

 another ten or twenty years medicine may have 

 ceased to be an art. It may become a science. 



