SPONTANEOUS GENERATION 313 



quire the exercise of the cold critical faculty more than 

 this one calm study in the unravelling of complex phe- 

 nomena, care in the preparation of experiments, care in 

 their execution, skilful variation of conditions, and inces- 

 sant questioning of results until repetition had placed 

 them beyond doubt or question. To a man of Pouchet's 

 temperament the subject was full of danger danger not 

 lessened by the theoretic bias with which he approached 

 it. This is revealed by the opening words of his preface: 

 "Lorsque, par la meditation, il fut evident pour moi que 

 la gdndration spontane*e e*tait encore 1'un des moyens 

 qu'emploie la nature pour la reproduction des 6tres, je 

 m'appliquai a de*couvrir par quels proce'de's on pouvait 

 parvenir a en mettre les phe'nomenes en eVidence." It 

 is needless to say that such a prepossession required a 

 strong curb. Pouchet repeated the experiments of Schulze 

 and Schwann with results diametrically opposed to theirs. 

 He heaped experiment upon experiment and argument 

 upon argument, spicing with the sarcasm of the advocate 

 the logic of the man of science. In view of the multi- 

 tudes required to produce the observed results, he ridi- 

 culed the assumption of atmospheric germs. This was one 

 of his strongest points. "Si les Proto-organismes qne nous 

 voyons pulluler partout et dans tout, avaient leurs germes 

 disse'mine's dans I'atmosphere, dans la proportion mathe'ma- 

 tiquement indispensable cet effet, 1'air en serait totale- 

 ment obscurci, car ils devraient s'y trouver beaucoup plus 

 serre*s que les globules d'eau qui forment nos images 

 e*pais. II n'y a pas 1& la moindre exage'ration. " Recur- 

 ring to the subject, he exclaims: "L'air dans lequel nous 

 vivons aurait presque la densitd du fer." There is often 



a virulent contagion in a confident tone, and this hardi- 



SCIENCE 14 



