110 EXPLANATIONS. 



sent state of the science, and the latter affording us 

 proofs — proofs, at least, satisfactory to many of the 

 best anatomists of our age — of a plan of individual 

 development, which may be called the living pic- 

 ture of the advance of species, during the vast ages 

 chronicled by the sedimentary rocks. A third 

 series of vestiges now remains for consideration — 

 namely, those which hint at originations and mo- 

 difications of organic beings in the current era. 



The objections to the occasional production of 

 organic beings, otherwise than ex ovo, do not ap- 

 pear to have been softened by the publication of 

 my former volume. All reviewers, with the single 

 exception of the British and Foreign Medical 

 Review, have intimated their continued scepticism 

 on this point. The experiment of Professor 

 Schulze, of Berlin, with decaying organic matter 

 floating in a flask to which common air was ad- 

 mitted, after passing through sulphuric acid, thereby 

 being deprived of all animal admixtures — an ex- 

 periment which ended in the non-production of 

 any animalcules or mould — is pointed to as con- 

 clusive. Explanations more or less plausible have 

 also been offered for the origin of the entozoa, 

 the parasites of civilization, the pimelodes cy- 

 clopum, etc. I should fear to weary the reader 



