ORIGIN OF LOWEST ORGANISMS. 



An easier position to establish would be, that the 

 Bacterium or the Tontla were occasionally links in the 

 life-history of fungi, or that the gonidial cell was an 

 occasional link in the life-history of a lichen. This 

 doctrine would leave the other more difficult problems, 

 as to the possible existence of supplementary 

 modes of origin for such organisms by Heterogenesis 

 or by Archebiosis perfectly open questions. 



To establish the position that Bacteria are occa- 

 sional links in the life-history of fungi, it would be 

 only necessary to show that some of the Bacteria 

 which develop into fungi through Leptothrix have 

 derived their origin from pre-existing fungi. This is 

 the view which Hallier* has endeavoured to establish ; 

 it is also the doctrine of M. Polotebnow,t and one, 

 moreover, to which Professor Huxley J inclines. Even 

 this mode of origin for Bacteria, however, has not been 

 so decisively established as might be desired. With 

 regard to Tornlce, we do possess sufficient evidence 

 tending to show that some of them may arise from 

 pre-existing fungi, and we are equally certain that 

 some gonidial cells are thrown off from lichens. The 

 analogical evidence is, therefore, in favour of the view 

 that minute particles which are budded off from the 

 mycelium of certain fungi, may subsequently lead an 



* Phytopathologie, 1867. Hallier seems, however, strongly 

 inclined to disbelieve in the origin of these organisms by Hete- 

 rogenesis or by Archebiosis. 



t Sitzungsber. der K. Akacl. zu Wien, 1870, Band lx.-, Heft iv. 



t Quarterly Journal of Microscopical Science, Oct., 1870, 



