1894 THE MICROSCOPE. 39 



On Spontaneous Generation. 



ByC. a. McCAMM., 

 st. paul, minn. 



Beginning with Aristotle and for twenty centuries 

 after him, men found no diflBculty in believing in cases 

 of spontaneous generation. They even believed that 

 creatures as high in the scale of being as the frog were 

 products of spontaneous generation. The discovery of 

 the microscope dispelled a vast number of the beliefs 

 that were held concerning it but also brought into view 

 a world of life composed of creatures so minute as to 

 suggest the probability of a passage from atoms to or- 

 ganisms. The difficulty in assigning an origin to the 

 multitude of life found in liquids exposed to the air and 

 in stagnant pools led to this theory. The scientific 

 world was until late divided into two hostile camps upon 

 this subject. Among the upholders of the theory were 

 Buflfon and Neadham and later F. A. Pouchet in France 

 and Dr. Bastain in England. Among its opposers were 

 Francesco, Redi and later Pastuer and Tyndall. 



Redi proved that the magots which are found in putre- 

 fying flesh were produced by the flies which are always 

 found buzzing around the meat and alighting on it. The 

 magots, he thought might be the half developed progeny 

 of the flies. The guess led to experiments which estab- 

 lished its truth. But it remained for Tyndall to give the 

 death blow to this theory. After years of most careful, 

 intelligent and laborious experimenting he proved that 

 the formation of bacteria was not the result of vital 

 forces at work in the infusion itself but was due to con- 

 tact of particles, which are found floating in the air, 

 with the infusion. 



He prepared sixty flasks containing infusions of beef, 

 mutton, turnip and cucumber ; these he packed carefully 

 and transported to the Alps. The infusions^were pre- 



