86 MAJOR W. McAI'AM ECCLES. A].S.. yi.b., F.K.C.S., K.A.M.C.^ ON 



intermission ; if it did not. tlie whole machine wculd ccme to 

 a standstill. 



The heart beats " normally 72 times in each minute, a little 

 more often than once a second. An easy calculation proves 

 that it beats -1320 times an hour. 103,680 times a day, and no less 

 than 37.8.1:3,200 times a year ! Yet it will go on working for 

 70 years without wearing out ! Of course the heart is a living 

 structure, and unlike an inorganic machine, such as an engine, 

 it is being constantly invigorated by nourishment, which is very 

 different from the extraneous oil lubricating a machine. But 

 the heart, just like an engine, will not stand being tampered with. 

 If grit be allowed to find its wayinto the delicate parts of an engine,, 

 irretrievable damage may ensue. Just so if a poison is con- 

 tinually reaching the heart by the blood its muscle will wear 

 out." One very common poison to act in this way is alcohol. 

 Taken by the mouth, absorbed into the circulation from the 

 stomach, carried by the veins to the heart, it permeates the 

 delicate muscular fibres, and causes them to wear out," and to 

 cease working sooner than they otherwise would. 



Death by the Action of Micro- org axisms. 



Another law of Xature is that a dead body shall be resolved 

 into its constituent elements. Such a dissolution is brought 

 about by the action of parasites. From this separation of 

 highly complex animal matter into the elemental material of 

 which it is formed, the growth of other living beinss is permitted ; 

 and thus again the law of dissolution, like the law of death, is a 

 most beneficent one. 



Bacteria. 



But there are parasites which actually bring about death 

 before their colleagues can occasion dissolution. These parasites 

 are in the main microscopic li^-ing creatures, some of them so 

 minute as to require some of the highest powers of the modern 

 microscope to detect them. The varieties of these organisms 

 are many. Some of them are quite harmless to the human body, 

 while others if they get a foothold wiU kiU in a few days or even 

 a few hours. Many of the pathogenic organisms belong to the 

 vegetable kingdom : are plants, in fact, of the type of fungi, and 

 are termed bacteria. They are three readily differentiated 

 forms : — 



1. The coccus. 2. The baciUus. 3. The spirillum. The 

 coccus is a minute spheroidal bacterium. It multiphes extra- 



