678 TYNDALL ON SPONTANEOUS GENERATION. 



organisms they dealt with, the notion was banished forever. But the dis- 

 covery of the microscope, revealing a world of life formed of individuals so- 

 minute — so close, as it were, to the ultimate particles of matter — as to sug- 

 gest an easy passage from atoms to organisms, revived the dj^ing doctrine. 

 Dr. Tyndall now traced its support by Buffon and I^eedham, (1748) and the 

 experiments with a contrary tendency of Spallanzani, (1779) Schulze, (1836)) 

 Schwann, Helmholtz, Schroeder, and Yon Dusch.. In 1859 Pouchet, a vig- 

 orous and ardent writer, strongly influenced opinion in favor of spontane- 

 ous generation. In view of the multitudes of motes required to produce- 

 the observed results, he ridiculed the assumption that there are atmospheric- 

 germs. If there were, indeed, said he, the Lumber that are mathematically 

 required, the air would be entirely obscured by them. The germ clouds- 

 would be much thicker than the rain clouds. But had Pouchet known that 

 the blueness of the ethereal sky is actually due to the suspension of innu- 

 merable particles in the air upon which the sun s^hines, he would hardly 

 bave ventured on this line of argument. Pasteur, however, published his^ 

 classical paper in 1862, and his main position has never been shaken. He 

 has applied the knowledge won from his inquiries to the preservation of 

 wine and beer, to the manufacture of vinegar, and to the staying of the- 

 plague which threatened destruction to the silk husbandry in France. Prof. 

 Lister has thanked him in a published letter for having furnished theonlj'' 

 principle which would have conducted the antiseptic system in surgery to. 

 a successful issue. Our knowledge has been greatly extended by Prof. 

 Cohn, of Breslau. " ISTo putrefaction," he say&, " can occur in a nitrogen- 

 ous substance if its bacteria be destroyed and new ones prevented from en- 

 tering it." Bacteria are the minute animals, so called from the rod-like 

 appearance of some of them, which are now thought to be at the root of the 

 disease as well as of putrefaction. According to this view, a contagious- 

 fever may be defined as a conflict between the person sraitten by it and a 

 specific organism which multiplies at his expense, appropriating his air- 

 and moisture, disintegrating his tissues, or poisoning him by the decompo- 

 sitions it causes. 



Prof. Tyndall proceeded to refer very briefly to his own studies on the- 

 subject since 1869, and more in detail to his experiments made this summer 

 on the Bel-Alp, above the Ehone valley, the spot 7,000 feet above the sea- 

 being selected for the sake of the purity of the air and its freedom from> 

 organisms. In describing an actual experiment he would assume he was^ 

 accompanied by some eminent and fair-minded, member of the medical pro- 

 fession, who entertained views adverse from his, because it was obvious- 

 that to an important portion of the medical press of London he had not as- 

 yet succeeded in rendering this question clear. Sixty flasks would be filled 

 in the manner described in the lecture, with an infusion of beef, mutton,, 

 turnip and cucumber, sterilized by boiling and hermetically sealed. They 

 are transported to the Alps. It is the month of July, and the weather is- 

 favorable to putrefaction. At the B^eli-Alp fifty-four flasks are counted out 



