174 FOREWORD 



filaments, and of the various surfaces formed by the aggregation of 

 these filaments, is suggestive of the methods of modern histological 

 science. He shows that the substance of the filaments is developed 

 from a fluid exuded through the outer surface of the animal. The 

 structure of pearls, and their relation to the growing moUusks, is 

 discussed at considerable length. 



In treating the length of geological time, Steno was clearly ham- 

 pered by the church doctrine of the time, to which he himself sub- 

 scribed. Accepting as correct the Usher chronology of the 

 Scriptures and the Noachian conception of the universal deluge, it is 

 small wonder that Steno fell into error in evaluating geological time. 

 " There are those," he said, " to whom the great length of time seems 

 to destroy the force of the remaining arguments, since the recollec- 

 tion of no age affirms that floods rose to the place where many 

 marine objects are found to-day, if you exclude the universal deluge, 

 four thousand years, more or less, before our time" (p. 258). He 

 thinks it possible to affirm that the shells dug from the hill on 

 which Volterra was built, were formed more than three thousand 

 years ago. The remains of elephants and extinct animals which 

 were found in the valley of the Arno, and which we now know 

 crossed from Africa on a land bridge in Tertiary times, Steno was 

 forced to regard as the mired pack animals which had been brought 

 by Hannibal's army on its way to besiege Rome. 



Now that the Latin text of Steno's work has become available 

 through republication, it seems opportune to make his argument 

 accessible in English, and it is believed that Dr. Winter's rendering 

 of the learned Dane's Prodromus, with annotations and with a 

 brief account of his life and writings, will be welcomed by students 

 of natural science. 



Wm. Herbert Hobbs. 



Ann Arbor, Michigan, 

 February, 191 6. 



