STATE DAIRY ASSOCIATION. 615 



is the general name for the whole group. In attempting to give an ade- 

 quate idea of the size of these plants I am embarrassed by the mind 

 being unaccustomed to appreciate very small fractions, or large numbers 

 necessary to express exact measurements of these individuals. It would 

 take a hundred and eighty million to cover the end of your lead pencil 

 and one billion eight hundred to sheath the outside of your finger nail. 

 Is there any wonder that danger lurlvs in the small things, when the 

 bacilla causing each of the twenty-eight now recognized contagious dis- 

 eases could be taken into the system through a liole much smaller than 

 the central canal of the finest hair? That such wliolesale contagion is 

 not likely to occur, we shall see before the end of our paper. But what 

 matters the minuteness of the elements when numbers compensate? Very 

 minute marine animals form an aggregate formation fw islands and 

 perhaps continents. 



• "Wherever any form of vegetable or animal life is capable of existing, 

 there we are certain to find bacteria; in the air, earth, water, on every 

 portion of the outside of the body, in the mouth, nasal passages, alimen- 

 tary track and lungs. They readily enter most parts of the system 

 through ordinary channels, and even penetrate the unbroken skin; con- 

 trary to the general belief, none of them are. exhaled in normal breathing. 

 In the air the number varies from the very high allowance in cities of 

 2,500 per quart to the very moderate propoi-tion of 300 per quart in the 

 country, while on the tops of high mountains the number is very small, 

 and probably on snow-capped peaks the air is free from all germs. 



It is not the number that is to be dreaded, but the kind. Compara- 

 tively few disease-producing forms originate in the air. In the water 

 the condition is somewhat different, as this is the ordinary mediimi best 

 suited for their development. Water flowing from deep springs is prac- 

 tically without bacteria imtil it reaches the surface. Unlike the air, 

 water is the ordinary source and common carrier of many fatal germs. 

 Bad water means bad health. A large number of bacteria may mean 

 simply filthy water, and yet it may not contain the organisms of any 

 specified disease. Our food is often teeming with these forms of 'jerm 

 life, and milk may contain as high as ten billion microbes per quart. 

 Indeed, about half of this number is found in the good milk sold on our 

 streets. Bacteria in great numbers are almost everywhere; they appear 

 in the alimentary track of the child from four to eight hours after birth, 

 and stay with it through its pilgrimage and are the last to leave it when 

 dust returns to dust, ashes to ashes, the body to the earth which gave 

 it. Let us not despair, for most bacteria are our friends and are neces- 

 sary to our comfort. Indeed we are dependent upon them, for if it were 

 not for the presence of certain forms in the alimentarj' track the process 

 of digestion would be impossilile. .\nimMl lif(> witliout bacteria is out of 

 the question. 



Each plant has a single cell and is provided with a tough cell wall that 



