vin BIOGENESIS UIO \ r.h &amp;gt;&amp;lt;;KNKSIS 851 



f rms of great simplicity, endowed, like existing 

 fungi, with tin- power of determining the formation 

 it new protoplasm from such matters as ammonium 

 carbonates, oxalates and tartrates, alkaline and 

 earthy phosphates, and wain, without the aid of 

 light. That is the expectation to which analogi 

 cal reasoning leads me ; but I beg you once more 

 to recollect that I have no right, to call my 

 opinion anv thing but an art of philosophical 

 fait!,. 



S&amp;lt;&amp;gt; much lor the history of tlir progress of 

 RedTs great doctrine of Biogenesis, \\liich appears 

 to mi-, with the limitations 1 lia\c expressed, to 

 be victorious along the whok line at the present 



dav . 



A- ie-.irds the second problem offered to us by 

 Keili, whether Xenogeiiesi* obtains, side by side 



\\itll Homogellesis. whether, that. is. there exist 



not only the ordinary living things. gi\ing rise to 

 otVspring \\hich run through the same cvcle as 

 themselves, but also others, producing offspring 

 which are of a totallv ditferent character from 

 themselves. the ivseaiches of two centuries hnve 

 led to a ditferent result. That the grubs found 

 in galls are no product of the plants on 

 \vhieh the galls grow . but are the result of the 

 introduction of the i-gy-s of insects into the sub 

 stance of these plants, was made out b\ Vallisnieri. 

 K lumur. and others, before the end of the : 

 half of the eighteenth century. The tapeworms. 

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