32 



Summarising the results obtained, we see that nutrition 

 influences the médian value and the variability of the 

 characters. Besides it appears that the sensibility-coef6cient 

 of the médian is very différent: 



1. for différent species compared among each other. 



2. for différent characters of the same species. 



And about the variability we saw: 







1. that with good nutrition the variability-coeffiicient —: 



is fairly constant for différent characters of the same species, 

 but very divergent for the différent species. 



2. that with bad nutrition two of the species studied 

 show great différences between the variability-coefi6cients 

 of the différent characters of the same species, while 

 with one species the variability-coefficients of the various 

 characters diverge relatively little. 



3. that the sensibility-coefl&cient of ^ diverges greatly 



for différent species and characters and varies between 

 — 1.40 and -+- 0.29. 



4. that for some characters the sensibility-coefficient of 



^ is positive and good nutrition results in an increase of 



the variability ; while for other characters, even of the same 

 species, this coefficient is négative. 



In what précèdes, there has only been question of those 

 characters which show symmetrical or sensibly symmetrical 

 curves and which, when expressed in constants, yielded 

 the results mentioned. 



From thèse the curve of the number of branches of the 

 third order of Iberis amaru, grown on the sand, déviâtes 

 entirely, being a semi-curve. For the culture on fertile 

 earth, however, this same character gives a symmetrical 

 curve. In fig. V this latter is very flat and extended in 

 length, as the observations were divided over a great number 

 of intei*vals in order to allow a comparison of the two 



