19 



leaves curved toward the decayed mother bulb from whicli the infec- 

 tion was received, as in case of one described by Dr. Wakker, but 

 this I neglected to determine. 



INOCULATIONS OF 1898, 



The following year these experiments were rei>eated. All the plants 

 were in the same greenhouse. The night temjperature of the house 

 for a month or two, during which symptoms were slowly extending in 

 the hyacinth leaves, was 10° to 18° C. ; the day temperature was 21° 

 to 31° C. Subsequently, during May and June, the temperature 

 fluctuated more, and some of the time it was considerably higher, 

 especially in the daytime — that is, 10° to 20° C. by night and 30° to 

 46° C. by day. On quite a good many days during this period the 

 air temperature for some hours ranged from 35° to 40° C. — i. e., too high 

 for the growth of tliis organism, as shown by maximum temperature 

 experim<mts, and probablj'^ high enough to have been of material aid 

 to the plant in resisting the attack of the parasite. 



SERIES 3 (hyacinths). 



The third series of inoculations was made January 29. Seven 

 well-grown hyacinth plants, not yet in bloom, were selected for this 

 purpose, and eight uninoculated j^lants were held for comparison. 

 All were inoculated from an alkaline beef-broth culture (No. 4, Jan- 

 uary 25), using a hj^podermic syringe. Two were inoculated by 

 means of numerous punctures into the short, unexpanded inflores- 

 cence. The other five plants were inoculated in the apical i)art of 

 the leaves. The leaves at this time were about one-half grown 

 (10 cm. long), and three on each plant were inoculated. Including 

 what was wasted, about seven to eight cc. of the cloudy fluid was used 

 on the seven plants. These plants were single-flowered and of three 

 sorts — flowers large white with a tinge of blue, flowers large creamy 

 white, and flowers large pink with a deeper strijje down the center 

 of the i)etals; names unknown. The germs used for this series of 

 inoculations and all of the following were descendants of those iso- 

 lated in June, 1897, from the yellow, broken-down bundles in the 

 bulbs of the plants inoculated February 16 (see first series). 



Result. — Four of the check plants were destroyed by a rapid soft 

 white rot. The other four were sound and free from all trace of the 

 yellow disease when examined June IS. 



All of the seven inoculated plants showed distinct above-ground 

 symptoms, the progress of which was slow. Three of these were 

 attacked in the spring by a rapid soft white rot. In one of tliese, 

 which was dug early, the unsoftened part of the bulb showed two 

 yellow bundles. Tlie other four — i. e., those not attacked by tlie soft 

 rot, were dug June is. Tlie bulbs wen^ souikI externally. Two 

 were sound internally, so far as could be determined by the unaided 



