148 OBSERVATIONS ON THE CALIFORNIA VINE DISEASE 
observations of Pierce, that they were in the latter, or, at least, 
іп an advanced stage; for this writer says: “ The time when the 
roots become diseased is difficult to ascertain, and will probably 
not be known before the nature of the malady is determined. 
. . . At present I incline to the opinion that the extremes of the 
vine show the early signs of disease at nearly the same time.” 
Viala and Sauvageau observe that “the disease gradually de- 
scends towards the base of the shoots, becomes manifest in the 
arms, the trunk, and later reaches the roots."? 
My personal observations are in perfect accord with those of 
the authorities just cited. I have observed that the roots of 
diseased vines are not affected at the inception of the disease and 
will take the longer to show signs of weakness the healthier the 
vine, and the greater the amount of foliage still remaining in 
normal function. ТЕ is evident that when a vine is affected in all 
its shoots with a severe apoplectic attack, disorders in the finer 
roots will immediately take place; the sudden die-back of the 
shoots almost to the spurs will be followed by corresponding 
death in the rootlets—but if we take a vine that is diseased only 
in a few of its shoots, then its roots will not be different in ap- 
pearance from those of the neighboring healthy vines. Visible 
symptoms of disease in the roots do not precede the appearance 
of disease in the shoots. When the roots decay it is because 
they are in a weakened state and external conditions are ѕирег- 
inducive; this is evidenced by the fact that roots will dry-rot in 
one soil and soft-rot in another. 
The visible seat of the disease being in the foliage, then, ue 
popular opinion vouchsafes, and our own and other investigators 
observations substantiate, it will be in the study of the behavior 
of the diseased vines and of the anatomy of pathognomonic 
tissues that we will find the answer to the question: What is the 
nature of the California vine disease? 
I shall attempt to answer this question. 
Шш the preceding chapter I established that the California vine 
disease does not differ in method of attack or propagation from 
Folletage, and showed also that the foliar characteristics of the 
* Loc, cit., 51. 
* Loc. cit., 99. 
