BIOGENESIS AND ABIOGENESIS 109 



foible.' With your permission, I propose to cut up ' A Devon- 

 shire Man ' ; but I leave it to the public to judge whether, 

 when so employed, my occupation is to be referred to the former 

 or to the latter category " (Life, i. pp. 325-6). 



6. " On the Geographical Distribution of the Chief 

 Modification of Mankind" (op. cit., pp. 404-12. Read 

 June 7, 1870. Sci. Mem, iii, xxxiii, p. 564). 



7. " Presidential Address to the British Association at 

 Liverpool" (Rep. Brit. Assoc. (1870), 1871, pp. lxxiii- 

 lxxxix. Sci. Mem., iii, xxxiv, p. 572. Coll. Essays, viii, 

 p. 229). — This deals with " Biogenesis and Abiogenesis," 

 the origin of life from life, as against " spontaneous 

 generation," or conversion of non-living matter into living. 

 After a sketch of the history of the question, showing 

 how abiogenesis had gradually been disproved for the 

 more obvious organisms, an account is given of the way 

 in which Pasteur aiid others disproved it for bacteria, 

 the last stronghold of the spontaneous generationists. 

 Huxley himself repeated these experiments, and some of 

 the flasks of sterilized hay-infusion he employed long 

 afterwards figured on his lecture bench. 



But while the address clearly sets forth the disproof 

 of all supposed cases of abiogenesis so far as the present 

 is concerned, it proceeds to the logical conclusion that as 

 an " act of philosophic faith " it is necessary to believe 

 that the first living matter was so formed. It is suggested 

 that the earliest organisms must have been independent 

 of light, feeding in much the same way as fungi do now. 

 This last view has not found general acceptance. 



Prominence is given to the practical bearing of re- 

 searches on bacteria, and other lower forms, on the treat- 

 ment of contagious and infectious diseases, whether of 

 human beings, animals or plants. The pioneer work of 

 Pasteur on the silkworm disease known as pebrine is 



