Thus, it will be seen that single conidium 3 gave rise to sixteen clearly 
lefined saltants; C5, to one; C1, to two; and C2, to seven—demonstrating 
ibsolutely that these saltants were not due to impurity of cultures. Evi- 
lently the saltant sectors do not result from contaminations. 
FREQUENCY OF SALTATION 
It is impossible to give any mathematically accurate statement as to 
he frequency of saltation in Helminthosporium. One hundred and 
wenty-six variant sectors were selected, transferred, and more or less 
tudied; and this number could easily have been doubled or trebled. It 
s not probable that all the forms in these sectors were truly saltants; 
loubtless some of them were mere modifications, but the number that were 
Jermanent in character is large. How many of these saltants agreed with 
‘ach other in observable characters it is also impossible to say, but since 
hey arose independently it may be that they do not often agree absolutely. 
[he percentage of saltants, based on those theoretically possible, is, how- 
‘ver, small even in races that are most actively saltating. Thus in a colony 
) cm. in diameter there are probably more than 5,000,000 cells, and theo- 
etically it appears probable that saltation occurs in a single mycelial cell, 
yr perhaps by the union of two cells, yet saltations occur with even less 
requency than one to each 6-cm. colony, therefore less than once out of 
},000,000 possibilities. In this connection, though no direct comparison 
s possible, it may be noted that East (47) considers the occurrence of twelve 
nherent variations in observations made on 100,000 hills of more than 700 
varieties of potatoes, that is, about 1:10,000, as an unexpectedly high rate 
