HEREDITY 83 



and more radical theory which he called the " continuity 

 of the germ-plasm." This is the theory that holds at 

 the present day. 



There are certain things that have proved a fertile 

 source of controversy in relation to the theory of here- 

 dity, and the chief of these is the question of the trans- 

 mission of acquired characteristics. Many biologists 

 have believed that gains or losses due to the influence 

 of nutrition and of surroundings may be transmitted 

 from parent to offspring. Numerous cases have been 

 cited in support of this belief, and many workers in 

 various branches of science, for example Virchow and 

 Eimer, have written in support of it. On the other 

 hand we have men such as Weismann and Ray Lankester 

 who deny the transmissibility of such characters. 

 Others there are, not few in number, who pin their 

 faith to a modified form of Weismann's theory. 



Sufficient has been said about heredity to show that 

 it forms an integral part of Biology, and that it must 

 not be neglected, if Biology is to be thoroughly grasped ; 

 and nothing more is necessary, as the subject has already 

 been ably dealt with in a previous volume in this series. 



