January 3, 190"2.] 



SCIENCE. 



17 



as revealed by these statistics of attend- 

 ance. Geo. B. Geemann. 



SCIENTIFIC B00E8. 

 Die EntwicTclung der Biologic im 19. Jahrhun- 

 dert. Vortragauf derVersammlung deutsch- 

 er Naturforsclier Zu Aachen am 17. Sep- 



considerable on the development of minute 

 anatomy in the nineteenth century that, not- 

 withstanding the fact that he met his early 

 and untimely death in 1802, his should be rec- 

 ognized as one of the great influences in the 

 development of biology in the nineteenth cen- 

 tury. The omission of the name of any 

 American investigator is more in the nature 



tember, 1900, gehalten von Oscar Hertwig. 



Jena, Gustav Fischer. Pp. 31. 



The advancement in knowledge of organic 

 nature was so remarkable during the nine- 

 teenth century that it is of unusual interest 

 to have the progress in biology summed up 

 by one of the leaders in the movement. As 

 might be expected from Hertwig's well-known 

 powers of clear exposition, the reading of 

 this lecture is enjoyable; the line of thought 

 is not difficult to follow and the analysis of 

 the subject is as simple and direct as it is pos- 

 sible to make it within the limits of thirty- 

 one pages. It is, of course, impossible in many 

 instances to do more than suggest the line of 

 influence of a group of men whose work has 

 been of epoch-making importance. The 

 names of most of the great leaders are men- 

 tioned categorically — and the list is a long 

 one, but it is a disappointment to miss any 

 reference to Bichat. His influence was so 



* Included under College. 170 students in law are 

 enrolled : loss of 15. 



of a blunder. However clear the general ac- 

 count of biological progress may be, it is in- 

 adequate if no place is found in it for such 

 names as Cope, Marsh and Gray or for the 

 mention of the embryological and cytological 

 researches of American investigators. 



The subject is naturally considered under 

 two main divisions — the progress in morphol- 

 ogy and that in physiology. In regard to 

 progress in morphology, the four following 

 factors are indicated as having had the 

 greatest influence : (1) The establishment of 

 the cell theory and the closely related proto- 

 plasm doctrine. (2) The development of the 

 science of bacteriology. (3) Progress in em- 

 bryology. (4) The doctrine of organic evo- 

 lution. 



The great influence of the cell theory is es- 

 pecially emphasized, not only as to its unify- 

 ing tendency iu uniting animals and plants 

 on the broad basis of similitude of structure, 

 but also as opening to naturalists the real 

 problems of the living organism. The dis- 



