TOMATO DISEASE IN GUERNSEY. 
17 
then the growing points of the larger root leaders become soft 
and brown, and higher up the cortex of the root becomes dis- 
coloured ; and when this has come to pass the terminal leaves 
of the branches at once begin to droop. The stem sections show 
that at first, at a very early stage of the disease, a small portion 
of the cambium layer (or its equivalent in the Tomato) has 
become broken down and tinted brown ; later on a second spot, 
probably on the side opposite the first, appears, and these gradu- 
ally grow until the whole circle of the cambium layer * becomes 
brown and rotten ; and it is not until this ring of disease is 
nearly completed that the plant " sleeps" ; and thus the outward 
manifestation of the disease comes too late to be of any use as a 
warning or indication of the danger, and a whole houseful of 
plants is often killed before it is known that the disease exists. 
The rotting of the cambium layer (including the inner cortex) is 
due to the presence of the mycelium of a fungus, which rapidly 
extends upwards, usually killing the plant when it has reached a 
height of from 12 to 18 inches up the stem. 
I wish now to draw attention to the fact that the growers in 
almost all cases ripen their fruit as far as possible upon the 
dying plants, and hence it is only reasonable to suppose that the 
Tomatos themselves, and probably also their seeds, contain the 
germs of the disease. After searching in vain for the fungus of 
this disease in the soil of a house freshly attacked, and after 
many ineffectual attempts at cures, I at last determined to test 
this question of the condition of the fruit. Sections of Tomatos 
from the diseased houses were made for me by Mr. Sinel, of 
Jersey, and these were sufficient to satisfy me that the disease 
may be perpetuated through the seed. I cannot, indeed, say that 
I have actually proved my point to the satisfaction of others, but 
I have opened up the question, and my hope is that it will now 
be taken up by experts, and my theory either confirmed or 
refuted. t The fruit chosen for my sections undoubtedly showed 
the presence of minute transparent hypli^e ; no spore-like bodies 
have been found on the hyphse, but Mr. Sinel, working with an 
* The term " cambium layer " is incorrect, but is useful in describing 
the position of the first appearances. The fungus does not attack the 
xylem directly, but commences its attack in the formative layer on the 
outside of the xylem proper. 
t The presence of hyph» in the seeds has since been confirmed be 
Mr. G. Massee, of Kew. 
O 
