A Bacterial Disease oe Alfalfa 9 
was reisolated on an agar slant. When compared with the original 
culture, the recovered organism was identical both in the hanging 
drop and when stained with aqueous fuchsin. The reisolated culture 
was again inoculated, June 25, by needle pricks into three different 
stems, and all of the inoculations gave positive results; the needle 
pricks showed a yellow, watery zone around the point of infection 
after nine days, and later turned black. When material from these 
diseased areas was examined microscopically, August 16, the same 
milky cloud appeared in the mount as has been described for field 
material, and swarms of motile rods were visible. 
In all, one hundred and two inoculations have been made with 
this culture, introduced either by scraping the stem or by needle 
pricks, and positive results have been secured with one hundred per 
cent of the infections. Control inoculations with a sterile needle 
have been carried along with all of the experiments, and in no case 
have any of the check plants developed symptoms of the disease. 
method of infection. 
In an effort to secure a satisfactory explanation of the method 
of infection, the writer spent over a month in the field where the 
disease is most prevalent. As a result of the daily observa¬ 
tions and the gross and microscopic examination of more 
than three hundred plants, collected at all stages of the disease, be¬ 
fore it made its appearance and until it was flourishing, he believes 
the following to be the most tenable and satisfactory solution of 
the question. 
This phase of the investigation was carried on at Gypsum, 
Colorado, where our first observations were taken May 4, 1909; 
this was early in the spring for this locality and altitude (over 6,000 
feet above sea level). The season was considered cold and back¬ 
ward, and a moderately heavy snow had fallen one week before; 
traces of this were still to be seen in the valleys, and the surround¬ 
ing hills and mountains were heavily covered. 
The alfalfa was just beginning to grow, the average height 
in the diseased fields being from iy 2 to 2 inches. Most of the 
plants had a yellowish green color due, presumably, to the cold. An 
examination of the young, succulent shoots showed that the epider¬ 
mis of practically every one of them was wrinkled just below the 
point of attachment of the first four or five leaves, and often this 
wrinkling extended half way to the next leaf below. The epidermis 
was loose from the tissue beneath and appeared to be too large for 
the stem. When this was peeled off, the underlying tissue had a 
yellowish, green color much like the diseased plants, but a micro¬ 
scopic examination of such material failed to show any micro-or¬ 
ganisms present. In those parts of the stem where this wrinkling 
