12 BEYOND THE LIMITS OF VISION. 



full grown ciliated monads, fifty millions of which, he tells us, 

 could easily disport in a drop of water. Now these germs when 

 they first became barely visible under the Doctor's famous 25th, 

 could not have been mucli smaller than the one hundred-thousandth 

 of an inch. Therefore they were composed of about 10,000 

 million molecules each. That is an aggregate of 10,000 million 

 molecules is the vanishing point of microscopic vision. But 

 even these, it strikes me, are enough to build up a very respect- 

 able little body. There are not as many parts in any house in 

 the land, bricks, boards, tiles, nails and all. 



The canning of fruits and vegetables is now a domestic art. 

 Every house-wife knows that if the cans are properly scalded and 

 sealed while hot, they will keep sweet for any length of time. 

 But if opened to the air they will sour and spoil in a very few 

 days. Now this last condition is simply the production in them 

 of enormous numbers of what is called the Bacterium termo, 

 about the smallest living thing that is known, somewhat oval or 

 cylindrical in shape, with two cilia or minute hairs at one end, 

 which lash the water, producing a rapid jerking motion. It is of 

 a plant nature, or at least is so called, and increases by sub- 

 division, in a short time completely filling the liquid and absorb- 

 ing all the nutrient matter. Then follow the tribes of the 

 infusoria, little voracious animals, which seem successively to de- 

 vour the bacteria and then themselves. But whence came the 

 bacteria and then the infusoria ? They were not in the water nor 

 in the fruit ; for if they had been, the preparation that had been 

 sealed up would have immediately spoiled. The first thing which 

 the microscopist sees with his favorite 8th or 10th is a swarm of 

 these full grown organisms lazily rolling or darting and frisking 

 about. They must have come then either from spontaneous 

 generation or from spores and germs let down into the infusions 

 from the air. But it is now pretty well established that there is 

 no spontaneous generation no life except through antecedent 

 life. Therefore the latter, or the air-germ theory, is the only 

 true explanation. But no one has ever seen these germs in the 

 air, and we must consequently suppose that they are beyond the 

 reach of microscopic vision. 



