226 Wisconsin Academy of Sciences, Arts, and Letters. 
Perc. (60). On the other hand, in the case of cabbage yellows 
(45) (Fusarium conglutinans Woll.) the resistant Wisconsin 
Hollander variety under extreme conditions (high soil tempera¬ 
ture) shows a high percentage of plants slightly affected with the 
disease. However, such plants resist the parasite so successfully 
that they continue their growth, and with the return of somewhat 
cooler conditions all symptoms of the disease disappear and the 
plants mature normally. In contrast to this, plants of the common 
susceptible Hollander variety of cabbage may entirely succumb 
to the disease during the extreme conditions of high soil tempera¬ 
ture. We thus have in the case of Wisconsin Hollander not a 
completely immune variety by any means, but unquestionably one 
which may be said to have a high degree of disease resistance. 
Moreover, as pointed out by Tisdale (78), this is a case of resis¬ 
tance acquired during the growth of the plant, since he has shown 
that very young seedlings of the Wisconsin Hollander variety are 
as susceptible as those of the common Hollander variety. 
Kelation of Environment to Kesistance 
The effect of environment upon resistance has been given only 
occasional attention by investigators. Vavilov (82) points out 
several cases where certain races of plants were equally resistant 
to given parasites when tried out under a variety of environments 
and in various parts of the world. However, we are not justified 
in concluding that in other cases environment does not have its 
effects. 
Biffen (7) and Spinks (70) point out a distinct influence of 
various fertilizers upon the resistance of wheat to yellow rust 
(Puccinia glumarum (Schm.) Erikss. & Henn.). Stakman and 
Aamodt (73), on the other hand, found that in the case of wheat 
rust (Puccinia graminis tritici Erikss. & Henn.) “the amount of 
rust was not changed directly by any fertilizer or combination of 
fertilizers, although date of maturity, degree of lodging, crinkling, 
shrivelling of seed, percentage of yellow-berry, and yield were 
affected profoundly.^’ Tisdale (79) states that a strain of flax, 
resistant to wilt (Fusarium Uni Boll.) under normal field environ¬ 
ment, showed a marked increase in susceptibility when grown at 
high greenhouse temperatures. The value of results recorded on 
the behavior of so-called resistant varieties in localities other than 
those in which they originated is often limited by the fact that there 
