4l8 THE HISTORY OF BIOLOGY 



Owen does only in a minor degree. Through their comparative anatomy 

 Siebold and Stannius made an extremely valuable contribution to the de- 

 velopment of morphological science. Each also laboured separately and pro- 

 duced important results. 



Stannius w^as especially many-sided, both as a teacher and as an in- 

 vestigator; he taught pathology, physiology, and anatomy and has made 

 valuable additions to our knowledge in all these spheres. As a physiologist 

 he became famous for his attempts at underbinding the va^^ious parts of 

 the heart of the frog; further, he investigated the nerves of the tongue with 

 reference to their functions of taste and movement, and also the dependence 

 of muscular contraction upon nervous irritation. As a comparative anato- 

 mist he was especially remarkable for the splendid work he wrote on the 

 peripheral nervous system of the fishes, which is still authoritative, in spite 

 of all the more recent work accomplished in that field. 



Siebold, as is evidenced by the share he took in the Comparative Anatomy, 

 devoted himself mostly to invertebrate research. In this sphere he was 

 without doubt one of the foremost of his age. With a view to furthering 

 the development of research in his own special sphere he founded, in asso- 

 ciation with Kolliker, the Zeitscbrift fiir wissenschaftUche Zoologie — the title 

 being chosen of set purpose in opposition to the soulless method of classi- 

 fication — which was started in i^^i. and has since been one of the chief 

 organs for the furtherance of biological science. In many specialized fields of 

 invertebrate research Siebold 's contributions have been considerable. Fore- 

 most in this regard come his investigations into parasites. It may be recalled 

 that even Rudolphi believed that intestinal worms arose as the result of 

 a diseased process in the host. At an early stage Siebold was quite convinced 

 that this kind of spontaneous generation could not be accepted as rational. 

 He adduced in proof of this argument the existence of large quantities of 

 eggs in the intestinal worms, which obviously indicated that these animals 

 reproduced themselves in the same way as other animals. But the question 

 that still required an answer was how the offspring of the parasites come 

 to harbour in a fresh host. As yet this question was insoluble. To answer 

 it required a knowledge of a phenomenon of evolution — the alternation 

 of generations — which was still unknown at the time and was elucidated 

 by another scientist, who must therefore be described in this connexion. 



Johannes Japetus Smith Steenstrup (1813-97) was the son of a priest 

 from Jutland, in Denmark; he studied in Copenhagen, becoming professor 

 of zoology there after having been a schoolmaster for some years. He was 

 an extraordinarily gifted and many-sided investigator, working in many 

 widely differing fields of research; particularly celebrated are his investiga- 

 tions of peat-mosses, which he explored not only for zoological, but also 

 for botanical, geological, and archsological purposes. He also discovered 



