SCIENTIFIC MEMOIRS. 



VOL. v.— PART XVII. 



Article I. 



Contributions to the Comparative Physiology of the Invertebrate 

 Animals, being a Physiologico-Chemical Investigation. By 

 Dr. Carl Schmidt*. 



[Published as a separate work at Brunswick, 1845.] 



Introduction. 



If we survey the animal creation — if we discern in the infinite 

 variety of external aspect the necessary result only of an internal 

 structure — if, from numerous observations on the development 

 of these forms, from original unity in the cell to their utmost 

 complexity, we distinguish certain common morphological pe- 

 riods, which we unite into typical laws of formation — lastly, 

 if ascending from the simplest to the most compound, we en- 

 deavour to comprise forms corresponding to similar stages of 

 development «* natural orders or families, the question urges 

 itself upon us, Does an analogous combination of the chemical 

 go hand in hand with the homonymous development of the mor- 

 phological elements or not? in short, what connexion is there 

 here between form and composition, between the elementary con- 

 stitution of matter and its external, mathematically-definable and 

 appropriate limitation in space? Although physiological che- 

 mistry has made such extraordinary progress within the last few 

 years, nevertheless in this direction barely anything has been 

 done ; and deductions by analogy from existing observations on 

 the Vertebrata are, as we shall see, inapplicable to the more simple 

 structures of the Invertebrata, from the Cephalopod down to the 

 Monad. Lastly, although sound logic and natural philosophy 



• Translated from the German by J. W. Griffith, M.D. 

 VOL. V. PART XVII. B 



