stevensI EXPERIMENT ON SPONTANEOUS GENERATION 27 



man was ready to deny the spontaneous development of mammals, 

 birds, fishes, and even insects, however small, here was anew field for 

 thought, and many scientists of high repute became champions of the 

 belief in spontaneous generation, or development de novo without 

 paternal organisms, of these minute creatures. With the poorly de- 

 veloped technique of the time the problem was not an easy one, and 

 with a less skilled experimenter than Pasteur the truth might long 

 have remained hidden. Pasteur's demonstration was however com- 

 plete, and so far as man yet knows, no organisms, large or small, 

 plant or animal, now live that do not spring into existence from parents 

 of their own kind. There is no evidence that spontaneous generation 

 occurs or ever has occurred. 



The spontaneous generation controversy led to the founding of the 

 science of bacteriology, and through it came improved surgical methods 

 and the prevention of contagious diseases. Many household acts and 

 arts, canning, cheese and butter making, preserving, pickling, as well 

 as various medical and surgical practices of the house, are based di- 

 rectly upon the assumption of the non-occurrence of spontaneous 

 generation. 



So important is the idea that germs of putrefaction and decay do 

 not arise de novo in putrescible liquids and so interesting is the con- 

 troversy historically that it becomes a fitting and interesting subject 

 for school experiment. The experiments may be conducted in this 

 way: Prepare seven tubes for containing clear beef broth. If you 

 can secure them use ordinary test-tubes (5-inch tubes cost about 

 two cents each). Ordinary bottles though not quite so convenient 

 answer every purpose. Clean the tubes or bottles thoroughly, dry 

 them, and plug each tube with cotton. Then place them in the oven 

 of your kitchen stove, and bake them just long enough to turn the 

 cotton slightly yellow, not long enough to burn it at all. This we call 

 sterilizing the tube. By baking it in this way we kill every living 

 thing that is in the tube, all of the microscopic germs, yeasts, etc., of 

 all kinds. Now prepare your broth to put in these tubes. You may 

 make the broth by allowing some chopped meat covered with water to 

 soak over night, and then squeezing it through a piece of cheese cloth 

 to get the liquid out. Boil this liquid and then pass it through filter 

 paper in order to make it clear. Any druggist will let you have a 

 piece of filter paper and will show you how to use it. When you have 

 gotten the broth clear place a little of it, say two inches deep, in each 

 of your test-tubes. In opening the tubes and pouring the broth in it 



