176 FRAGMENTS OF SCIENCE. 



corpuscles present, but there were abundant evidences of 

 the growth and development of the corpuscles. I also 

 saw a frog's heart still pulsating which had been removed 

 from the body (I forget how many days, but certainly 

 more than a week). There were other examples of the 

 same persistent vitality, or absence of putrefaction. Von 

 Recklingshausen did not attribute this to the absence of 

 germs germs were not mentioned by him ; but when I 

 asked him how he represented the thing to himself, he 

 said the whole mystery of his operation consisted in 

 keeping the blood free from dirt. The instruments 

 employed were raised to a red heat just before use ; the 

 thread was silver thread and was similarly treated ; and 

 the porcelain cups, though not kept free from air, were 

 kept free from currents. He said he often had failures, 

 and these he attributed to particles of dust having escaped 

 his precautions.' 



Professor Lister, who has founded upon the removal 

 or destruction of this c dirt ' momentous improvements 

 in surgery, tells us the effect of its introduction into 

 the blood of wounds. The blood would putrefy and 

 become fetid ; and when you examine more closely what 

 putrefaction means, you find the putrefying substance 

 swarming with infusorial life, the germs of which have 

 been derived from the atmospheric dust. 



We are now assuredly in the midst of practical mat- 

 ters ; and with your permission I will refer once more to 

 a question which has recently occupied a good deal of 

 public attention. As regards the lowest forms of life, 

 the world is divided, and has for a long time been 

 divided, into two parties, the one affirming that we have 

 only to submit absolutely dead matter to certain phy- 

 sical conditions, to evolve from it living things ; the 

 other (without wishing to set bounds to the power of 

 matter) affirming that, in our day, life has never been 



