622 On Spontaneous Generation. 



just as we now and then find a living toad in a solid rock. 

 But I trust these rare cases do not justify a general conclu- 

 sion as to the means which nature employs for the preserva- 

 tion of plants or animals. 



I have not alluded to any instances of plants being produ- 

 ced or transported to other localities in the ordinary manner, 

 or by known means, as I did not wish to lengthen my article 

 by the enumeration of observations which could not contri- 

 bute to render my views of the subject more plausible ; though 

 had I been aware of any fact in the whole range of ordinary 

 generation, which could altogether exclude the spontaneous 

 mode, I should not have undertaken to support the latter. — 

 But unless such a fact or facts be brought forward, I shall 

 adhere to what I think both rational and probable. 



As to the necessity of animals which require to be tended 

 by a parent being first called into existence in the adult state, 

 I perfectly agree with Mr. Blyth ; nor do I see any reason 

 why a plurality of individuals, comprising the two sexes, 

 should not have originated at the same time in the same place. 

 The necessity of this latter condition is, however, not abso- 

 lute. As the female organism is plainly the connecting link 

 between the male organism and nature, we are rationally led 

 to suppose that only females were produced by spontaneous 

 generation, with reference to such animals as present distinct 

 individuals of different sexes. In these the creative conatus 

 may have proceeded to give rise to spontaneous conceptions, 

 which, on account of the symmetrical structure and antagon- 

 ism of the two lateral halves of the primary organism, were 

 perhaps those of twins, of different sexes. In the hermaphro- 

 ditical animals and plants this higher power of creative de- 

 velopement may have followed an exogenous direction, whilst 

 the 21st, 22nd, and 23rd botanical classes of Linnaeus pre- 

 sent different modifications of the same principle. It is not, 

 however, my intention to expatiate on such mere supposi- 

 tions, and I am induced to enter even so far into the subject, 

 only to give some reason why, in my opinion, M. Turpin 

 was not quite warranted in shouting "Io triumphe I " when 

 he discovered an egg in the newly-formed adult Acarusjior- 

 ridus of Mr. Crosse. 



With reference to Mr. Prichard's observation, — " It would 

 be easy to discover districts situated respectively in North 

 America and in Europe, or in Equinoctial America, Africa, 

 and Asia, in which all the same physical conditions exist, 

 namely, a parallel temperature and elevation, a similar] soil, 

 and the same degree of humidity in the atmosphere, — yet the 

 species of plants in these several districts will be far from be- 



