28 THE B1UDSHAW LECTURE 



cases, the girl is the one that shows the defect, 

 whilst the boy escapes. 



From these cases it will be seen that neither in 

 sex, mental development, nor tendency to disease 

 need there be any resemblance. These are known 

 as dissimilar twins. 



MODKIIX VIEWS ON HEREDITY. 



It is almost impossible to allude to the various 

 defects and deformities, known to be hereditary, 

 without referring to the two modern schools of 

 research, the Mendelian and Galtonian or bio- 

 metrical school, each of which is doing excellent 

 work in its own sphere, but can see no virtue 

 whatever in the work of the other. To those 

 trained in biology, the Mendelian researches offer 

 a fascinating inducement to further study, and 

 appear to give a rational explanation of the 

 occurrence of variations which breed true. But 

 the precision that Mendel Avas able to give to his 

 researches by crossing peas, so that lie was able 

 accurately to predict numerical results, can never 

 occur among human beings, since such close in- 

 breeding and back-breeding never occur in any 

 human community. It is, nevertheless, much to 

 anticipate approximate results. 



The study of Men deli sm is essentially a study 



