MICROHYDRA DURINCr I907. 9I 



amazed ; and while the more cautious among naturalists set 

 themselves to verify what it was difficult to believe, there were 

 many who looked upon the alleged facts as impossible fancies. 

 The discoveries of Trembley were, however, speedily con- 

 firmed ; and we are now so familiar with the outlines of 

 the history of the fresh water polyp and its marvelous repro- 

 ductive powers, that we can scarcely appreciate the vividness 

 of the sensation felt when it was all novel and strange ; when 

 the leading men of our learned societies were daily experi- 

 menting on these poor worms, and transmitting them to one 

 another from distant countries by careful posts and as most 

 precious gifts ; and when even ambassadors interested them- 

 selves in sending early intelligence of the engrossing theme to 

 their respective courts." 



The discoveries, however, communicated by Trembley 

 that excited most astonishment were hardh^ such as will 

 appeal to the modern scientist as most important, or even as 

 any parts of the life history of an animal. It may be very 

 wonderful to learn that the Hydra can be chopped into many 

 pieces, longitudinal, transverse or diagonal, and that each 

 will, or ma^^ reconstitute itself an entire worm ; or that parts 

 of different individuals can be grafted together, or turned 

 inside out, like the fingers of a glove, and live happily ever 

 after. Such accidents can happen very seldom in real life, 

 and I, for one, am not ambitious that any person shall try 

 such experiments upon the subjects of this memoir. Suffice 

 it that we may learn under what circumstances it lives ; how 

 its daily meat is provided ; what methods of reproduction are 

 given to it ; and the wonderfully true story of the Alternations 

 of its Generations under favorable circumstances ; enabling 

 it, without passing through the gateway of a pseudo-death, 

 to break away from its earlier groveling state and assume for 

 a time the free, wandering life of a rover of the waters. 



It can hardly be necessary to describe that Hydra, familiar 

 to almost eveiyone, with its six or more tentacles and its 

 almost infinite powers of extension and retraction, in order to 



