34 BIOLOGICAL SOCIETY OF WASHINGTON. 



the whole field of that science as generally accepted he has co- 

 ordinated its facts and drawn from them a nnmber of new and 

 brilliant conclusions which have set the world to work on 

 entirely new lines of investigation. 



Professor Weismanu was logically led to the conclusion that 

 acquired characters cannot in any conceivable way be trans- 

 mitted. The first of the series of essays which have produced 

 such a sensation, that on the duration of life, was originally 

 read before the Association of German Naturalists and Physi- 

 cians at Salzburg in September, 1 88 1, and a short abstract of 

 it appeared in Nature for April 5. 1888 (Vol. XXXVII. p. 

 541). It was in this paper that he elaborated the theory that 

 unicellular organisms are potentially immortal. The second 

 of the series, that on heredity, was his inaugural agldress as 

 Pro-rector of the University of Freiburg, delivered June 21, 

 1883. It was in this that he first attacked the doctrine of the 

 transmission of acquired characters, and in it and the preceding 

 essay may be found the germs of all his later theories. The 

 remaining six essays appeared at intervals from 18S3 to 1S88. 

 Abstracts and reviews of them occured in Nature and the 

 English magazines, and long before the appearance in 1889 of 

 the admirable work containing an English translation of the 

 whole series with numerous additions and amendments by the 

 author and notes by the translators, "^ the controversy had be- 

 gun in which so many of the most eminent biologists of Europe 

 and America have taken part. 



Professor Weismann's general course of reasoning is some- 

 what as follows : It is universally admitted that all the higher 

 organisms consist of tissues made up of cells and that these 



* Essays upon Heredit}' and kindred biological problems. By August 

 Weismann. Authorized translation edited by Edward B. Poulton, Selmar 

 Schonland, and Arthur E- Shipley. Oxford, Clarendon Press, 1889. 



