336 FRAGMENTS OF SCIENCE 



Let us again take a definite case. Supposing my col 

 league to operate with the same apparent care on 100 in- 

 fusions or rather on 100 samples of the same infusion 

 and that 50 of them prove fruitful and 50 barren. Are 

 we to say that the evidence for and against heterogeny is 

 equally balanced ? There are some who would not only 

 say this, but who would treasure up the 50 fruitful flasks 

 as "positive" results, and lower the evidential value of 

 the 50 barren flasks by labelling them "negative" results. 

 This, as shown by Dr. William Roberts, is an exact inver- 

 sion of the true order of the terms positive and negative. 1 

 Not such, I trust, would be the course pursued by my 

 friend. As regards the 50 fruitful flasks he would, I 

 doubt not, repeat the experiment with redoubled care and 

 scrutiny, and not by one repetition only, but by many, as- 

 sure himself that he had not fallen into error. Such faithful 

 scrutiny fully carried out would infallibly lead him to the 

 conclusion that here, as in all other cases, the evidence in 

 favor of spontaneous generation crumbles in the grasp of 

 the competent inquirer. 



The botanist knows that different seeds possess differ- 

 ent powers of resistance to heat. 2 Some are killed by a 

 momentary exposure to the boiling temperature, while oth- 

 ers withstand it for several hours. Most of our ordinary 

 seeds are rapidly killed, while Pouchet made known to the 

 Paris Academy of Sciences in 1866 that certain seeds, 

 which had been transported in fleeces of wool from Brazil, 



1 See his truly philosophical remarks on this head in the "British Medical 

 Journal," 1876, p. 282. 



2 I am indebted to Dr. Thiselton Dyer for various illustrations of such differ- 

 ences. It is, however, surprising that a subject of such high scientific impor- 

 tance should not have been more thoroughly explored. Here the scoundrels 

 who deal in killed seeds might be able to add to our knowledge. 



