io The Colorado Experiment Station 
was absent, the tissue beneath the epidermis was not yellow, but a 
whitish green. In many plants, the loosened epidermis had the 
appearance of partially collapsed blisters, while around and under¬ 
neath these blisters the tissue seemed darker than normal and 
watery, with a suggestion of its having been frozen. Numerous 
lenticular breaks occurred in the epidermis of some stems. These 
might have been due to insect work although rather early in the 
season for this. Occasionally stems were found where the wrinkled 
epidermis had split open for a distance of one centimeter, exposing 
the moist pyrenchyma beneath. 
Ten days later, May 14, the epidermis of practically every stem 
in the field was split wide open from node to node over the first 
six internodes, the third to the fifth internodes being the most 
common. This splitting appeared to have begun with the wrinkled 
epidermis mentioned above, and had extended the whole length of 
the internode thereby exposing the succulent, moist tissue beneath 
to infection. It is the concensus of opinion of those who have ob¬ 
served this phenomenon, that both the breaking away of the epider¬ 
mis from the underlying tissue and the wrinkling and subsequent 
splitting are caused by freezing. A similar trouble ascribed to freez¬ 
ing has been observed in cherry trees and less frequently in the 
apple. Here the bark cracks and later splits open, exposing the 
green wood beneath just as in the alfalfa stems. 
Anyone who has ever lived in Colorado is familiar with the 
soil carrying capacity of our winds, and with this in mind, it is 
easy to understand how germ laden soil might be blown into these 
cracks, where it would adhere to the moist, exposed surface, and 
bring about a fatal inoculation. As a matter of fact, soil was al¬ 
ways found adhering to these surfaces, and, already, typical cases of 
the disease were developing. A microscopic examination of the 
tissues from the injured areas usually showed the germs to be 
present in great numbers, while ten days previous, that is before the 
splitting had occurred, there was no indication of any infection. 
Invariably, the disease appeared first and was worst on those parts 
of the stem where the epidermis had split and where soil had been 
caught in the open wound. A striking example of this was seen in 
an alfalfa field adjacent to a field which had been cultivated re¬ 
cently and sown to oats. The oat field was on the windward side, 
and with every gust, quantities of fine soil were carried over into 
the alfalfa. All along this side of the field, there was an aggra¬ 
vated attack of the disease, extending twenty to thirty feet into the 
alfalfa and the whole length of the field. Every plant was gray 
with soil and it is only reasonable to suppose that the disease was 
more severe here than in the more remote parts of the field because 
of the heavier soil inoculation. 
