22 MICROBES AND THE MICROBE-KILLER. 



The differences thus noted are due no doubt merely ta 

 varying degrees of activity or vitahty of the microbes. 

 The worst form of the disease is found at Panama, and 

 there no condition of health is sufficient to ward off the 

 attack. The old and the young are alike affected. Per- 

 sons in robust health may be struck down sooner than 

 those whose appearance would indicate a less power of 

 resistance ; and so powerful is the micro-organism that 

 causes it, so rapidly does it multiply, and so actively does 

 it operate to bring about a fermentation and destruc- 

 tion of the blood, that a few hours sometimes suffice to 

 bring death. It is a remarkable fact that, notwithstand- 

 ing the energy of the bacillus, the riiortality among chil- 

 dren is less than among adults. What does this show ? 

 How can it be accounted for? Easily enough on the 

 theory that there is something in the adult system to 

 favor the growth of the microbe which does not exist to 

 the same degree in the constitution of children before 

 the age of puberty. 



The microbe of cholera (see Plate XV.) is different 

 from that of yellow fever (see Plate XX., No. 79), but it 

 is equally energetic in growth and action, and causes 

 death quite as rapidly. Both probably arise from the 

 same source, though in different parts of the world, and 

 in that respect they are not unlikely to resemble the 

 common microbe of summer diarrhoea (see Plate XVI., 

 No. '61). This has been ascertained to exist in the super- 

 ficial layers of the earth, whence it may extend to water 

 or to the various articles used as food, the vital manifes- 

 tations of such micro-organisms depending on conditions 

 of season, heat, and moisture, and on the presence of 

 dead organic matter, animal or vegetable, or both. The 

 microbe so produced may pass likewise into the atmo- 

 sphere, whence undoubtedly it causes its evil effects in 

 the three diseases under consideration. Thus, it passes 

 into the system, where it brings about a process of fer- 

 mentation or decomposition, producing changes that re- 

 sult in giving the symptoms noticed in yellow fever,, 

 cholera, and diarrhoea: The microbe is not the same in 



