22 



Fig. 1. 



-Diseased scale of 

 hyacinth. 



neighboring bundle. 



ground jiarts of each of the eight other inoculated plants, and pro- 

 gressed slowly in the usual way. The notes upon plant No. 25, given 

 below, Avill answer for all. On June 14 the bulbs of these plants were 

 examined. One was free from bacterial infection so far as could be 

 determined 1 )y careful cutting and microscopic examination. One was 

 rotted and gone, as already noted. The six other bulbs were sound 

 externally but, within, each one showed distinct symi)toms of Dr. 

 Wakkers disease^-i. e., there were few to many yellow bundles full of 



bacteria in otherwise sound scales. In most 

 cases the plateau was also involved. Generally 

 the yellow disease was closely restricted to indi- 

 vidual bundles, the parenchjnna between them 

 being sound. In several cases, however, small 

 bacterial pockets had formed in the paren- 

 ch^^ma around a bundle; in one case all of the 

 parenchj^ma between two neighboring bundles 

 was yellow ; rarely, some of the smaller anasto- 

 mosing veins would be yellowed nearly to a 

 All of these features are shown in fig. 1 (from 

 plant Ko. 20). In no case was there observed an 3' rupture of the epi- 

 dermis of the affected scales or flow of the yellow slime between the 

 scales, the bulbs being examined too early for this stage of the disease. 



Notes on No. 25. — Inoculated February 7 in the apical part of 5 leaves by means 

 of a hypodermic syringe, suffused stripes resulting in each case. 



February 14. Leaves 12.5 centimeters long. No symptoms. The suffused stripes 

 due to the injection soon disappeared. The absence of symi)toms is surprising, con- 

 sidering the quantity of germs inserted and the time that has elapsed (seven days). 



March 1. Each of the five leaves now shows a yellow stripe down its center. 

 The breadth of these stripes is 3 to 6 mm. A few of them extend from near the 

 tip of the leaf almost to its base. Below the shorter stripes is a line of narrow, 

 interrupted, water-soaked spots. To either side of thj stripes the leaves are green 

 and normal in appearance. On one leaf only has any tissue shriveled, and that to 

 but a small e-ctent. The parenchymatic tissue in the stripes has become translu- 

 cent, while the parallel main bundles begin to be feebly browned. The greater 

 part of each leaf is still healthy, the symptoms being confined to the vicinity of 

 the injected parts. The sym:)toms a week ago (fourteenth day) were very slight. 



April 30. A marked increase of symptoms. The stripes now extend one-half 

 way down, two-thirds down, and entirely down to the base of the leaf. The parts 

 which were striped on March 1 are now dead and diaphanous or brownish. The 

 deepest brown is in the larger vascular bundles, and is feeble in comparison with 

 the brown veining of the cabbage produced by Pa. eampestris. At the ba-e of 

 these dead stripes the disease continues in the form of water-soaked stripes, which 

 are more or less interrupted, i. e., the surface symptoms disappear and reappear 

 a few millimeters lower. To either side of the dead, brown stripes there is a nar- 

 row yellow line beyond which the tissue is green and normal in appearance. Two 

 of the leaves have collapsed and dried out at the tip (1 cm. and 6 cm.). The slow 

 sidewise movement of the disease is very marked, and becomes astonishing when 

 we consider the enormous number of germs o.-iginally inserted into these leaves. 

 On one of these leaves there is an interrupted, water-soaked stripe in the narrow 

 yellow border, indicating a recent slight sidewise movement of the parasites. All 

 of these fcymptoms are shown in fig. 2. 



