257 



PRESIDENTIAL ADDRESS 



To THE Royal Society of South Australia, October 7, 1890. 



WEISMANN'S THEORY OF HEREDITY. 



N"o country in the world offers biological problems of more 

 entrancing interest than Australia, and it is often a source of 

 regret to me that the too-exacting requirements of a teaching 

 appointment, coupled with many duties both public and private, 

 are an effectual hindrance to the prosecution of some original 

 lines of research peculiarly Australian, any one of which might 

 have been appropriately made the subject of an address to this 

 Society. But as circumstances have rendered that impossible, I 

 must fall back upon the humbler role of an interpreter of other 

 men's thoughts, and therefore I purpose this evening to present 

 to you, in terms that I trust will be comprehensible even to those 

 who have had no special training in the subject, an exposition of 

 some recent biological theories that are exciting a good deal of 

 interest and discussion amongst the foremost investigators and 

 physiologists of the day. And indeed, the interest excited has 

 not been confined to the still narrow limits of the Scientific world, 

 but it has extended to the general educated public. 



The problems of heredity on which I intend to speak are not 

 new. They were under discussion as far back as the time of 

 Aristotle, but in our own days they have assumed a special pro- 

 minence and importance not only from their fundamental relation 

 to the Darwinian theory of evolution, but also from their asso- 

 ciation with the question of the transmission of disease and de- 

 formity, on which subject at last some light is beginning to be 

 shed. 



I must, however, disclaim any intention of laying before you 

 all the various theories that have been offered of late years in 

 explanation of the facts of heredity ; my aim is rather to set 

 before you without argument or comment the salient points of 

 an elaborate and luminous theory that has recently been put for- 

 ward by a distinguished German physiologist and philosopher, 

 w^hose views, in spite of many objections, have met with a very 

 general and favourable acceptance by biologists. And, whether 

 or not they receive entire concurrence, there can be little doubt 

 but that the theory of Professor "Weismann, by reason of its 

 extended scope and logical completeness, serves as the best work- 

 ing hypothesis yet extant for future investigations on the subject. 



