358 THE BEGINNINGS OF LIFE, 



no harm.' Again, silk-worms probably contained Psoro- 

 spermi^, and swallowed them at times with their food, 

 long before the outbreak of pebrine, and yet they were 

 not affected by a fatal epidemic disease. At last;, how- 

 ever, a particular change or morbid condition of their 

 tissues seems to have been initiated, in which Psoro- 

 spermise are especially prone to be developed — these 

 being, moreover, characterized molecularly by some 

 peculiar properties, so that they are capable of initiating 

 similar primary changes in other silk-worms ^. 



Looking, then, broadly at the various facts which 

 have been detailed in this chapter, how are they to be 

 explained by those who refuse to believe in Archebiosis 

 and Heterogenesis ? 



The only attempt at an answer which can be ad« 

 duced may be given in the words of Dr. Lionel Beale, 

 who says ^ : — ' The higher life is, I think, interpene- 

 trated, as it were, by the lowest life. Probably there 

 is not a tissue in which these germs are not ; nor is the 

 blood of man free from them. They are found not 

 only in the interstices of tissues, but they invade the 



^ The rational conclusion concerning pebrine, therefore, comes to be 

 very similar to that which we are compelled to adopt concerning the 

 mode of origin and propagation of 'flacherie' — another disease of silk- 

 worms, produced by feeding upon unhealthy or fermenting mulberry 

 leaves, and characterized by the presence of minute TorulaASk^ cor- 

 puscles throughout the body. ('Brit. Med. Journal,' Marcli 9, 1872, 

 p. 259.) 



2 'Disease-Germs,' 1870, p. 64. 



