36 RECENT DEVELOPMENTS OF THE 



First year, child at mother's breast 



I to 2h, cow milk chiefly 



3 '-*^ 52 

 6 to j^ 



8 to lo 



II to 15 



The glands in these cases are found to be in various stages of 

 enlargement, liquefaction, softening, suppuration, or calcification. 

 The bacilli are commonly present, but when calcification has 

 occurred they may be few or absent, and the nature of the disease 

 can then be proved by inoculation only. 



Lymphatic glands are accordingly believed to act as vital 

 filters. They are very active in early life and swell on the least 

 stimulus. If the stimulus be too great, their nutrition fails, the 

 tissue elements are destroyed, they degenerate, liquefy, suppurate, 

 and so throw off the virus. If they calcify, the virus or its 

 product remains in a harmless condition, although not thrown off 

 from the body by suppuration and abscess. 



It would appear, then, the opposing influences at work to 

 prevent the introduction of bacteria are much more effective than 

 have been commonly supposed ; and it is to these influences that 

 we owe our preservation from daily destruction. It has been 

 shown by Mr. Wallace, in his book on Darwinism (page 25), that 

 one fly would in three months of summer produce one hundred 

 millions of millions of millions — a number greater than exists at 

 any one time in the whole world, and that " to prevent this tre- 

 mendous increase there must be incessant war against these 

 insects, by insectivorous birds and reptiles as well as by other 

 insects, in the larval as well as in the perfect state, by the action of 

 the elements in the form of rain, hail, or drought, and by other 

 unknown causes. Yet we see nothing of this ever-present war, 

 though by its means alone, perhaps, we are saved from famine and 

 pestilence." 



How much more active is the contest between Bacteria and all 

 living things ! Countless numbers are being produced in a very 

 short time ; but few of these survive the opposing influences, in 

 spite of the property of immortality recently given to them by 

 Weisman. 



