( 408 ) 
the same, while they differ considerably among the three species. 
Doing the same with the badly-fed plants we find a much greater 
difference between the variability-coefficients of the various characters 
Q 
of the same plant. For this culture = varies between 0,10 and 
0,36, for the characters ot J/beris amara and between 0,127 and 
0,35 for those of Anethum graveolens. Hence it follows that the 
influence of nutrition on the variability of the different properties of 
a plant is not the same; how much this influence varies will be 
seen from what follows. 
Comparing for each character separately the variability of the 
well-fed with that of the badly-fed plants, we find that the difference 
between the variability-coefficients for the two cultures varies greatly 
in different cases; for some characters it is very considerable, for 
others small. In order to compare these differences, they were divided 
Q 
by the value of = of the well-fed plants, as stated. The resulting 
number is the sensibility-coefficient of the variability. This sensibility- 
Q 
coefficient of yy Sppears to vary between — 0,140 and + 0,29. In 
a comparison of various characters of the same species the fact that 
the roots of the bad culture had more or less penetrated into the 
subsoil, obviously is of no consequence, so that the results obtained 
with Malva vulgaris are also available here. 
() 
Or == ¢ 
The  sensibility-coefficient f Theris amara is for the four 
characters respectively — 1,40, — 0,17, — 0,08 and + 0,09; for 
the characters of Anethum graveolens — 0,74, — 0,105 and + 0,29; 
and for those of Malra vulgaris — 0,055, — 0,09 and + 0,12. Especi- 
ally with the first two plants these sensibility-coefficients diverge 
considerably, which proves how very different the influence of 
nutrition is on the variability of the different characters of a plant. 
By the same change in nutrition the variability of one character is 
hardly modified at all and that of another character of the same 
plant very considerably increased or diminished. 
It is very important to know in what direction the nutrition reacts 
on the variability, whether under unfavourable nutritive conditions 
the variability is either always greater, or generally smaller or whether 
the two cases are equally frequent. In this respect the table shows 
Q_ 
5 
us that for 6 out of 14 characters the sensibility-coeflicient of 7 
