162 



It will be at once recognized that the differences here are rather 

 less than many of the environmental differences and that there is no 

 security that these 26 foundation Hydras are really represented by 

 differentiated hereditary numbers of tentacles. Yet this table, as it 

 stands, embraces Hanel's proof that the number of tentacles is an 

 hereditary character in the 'pure line.' What evidence is there that 

 any one of the numbers of tentacles attached to those 26 parents is 

 really constitutional and not environmental? 



When we consider that Hanel's experiments extended over a 

 period of two years, that the different 'stem parents' were col- 

 lected and bred at different seasons, and that no data are given 

 by which it is possible to judge which of the races were kept under 

 a uniform environment this criticism greatly reduces the value 

 of her evidence for the existence of diverse genotypes. The 

 second point of Pearson's criticism deals with the inheritance 

 of the number of tentacles within the clone. The data were 

 subjected to statistical analysis by Miss Elderton and the cor- 

 relation between relatives was determined for different degrees 

 of relationship, within the population composed of the 26 clones. 

 A comparison of the correlations showed that there is a greater 

 resemblance between siblings and between parents and their 

 offspring than there is between 'uncle and nephew' or between 

 grandparents and grandchildren. This, as Pearson points out, 

 can not be due merely to the inclusion of diverse races in the 

 tables of correlation but indicates that there is an inheritance 

 of variations within the clone. From this evidence Pearson 

 concludes that Hanel's records show, not what she believed them 

 to show, but just the reverse; that regression is only partial, both 

 in the population and in the clone; that variatons are inherited 

 equally in both population and clone. 



