DISEASES OF PLANTS. 229 



is affected. At this stage if the weather continues unfavorable the 

 drought aids in Ivilling the weal^ened vines. Vines killed by heat and 

 dry weather lack the discolored leatlets, and the leaf stems and small 

 branches hang pendant on the upright stalks. 



A bacterial disease of cabbage, H. Garman {Kentuchj Sfa. Rpt. 

 1690, pj). dS-Mi). — In ISStl the cabbage in the vicinity of the station was 

 affected with a rot which seemed to be of a bacterial nature. In some 

 gardens two thirds of the heads were affected, more than half of which 

 were finally rendered worthless. The disease often appeared on the 

 outer leaves first, rendering the whole surface of the head black, but 

 more often there was an internal decay which resulted in the affected 

 heads breaking off at the stalks and falling to the ground. The condi- 

 tions most favorable to the rapid extension of the disease are moisture 

 and heat, and it was especially destructive during some very warm 

 weather in July. The invaded leaves become brown and watery at first, 

 and later, when the disease has reached an advanced stage, become 

 black. When thoroughly infested the heads give off" a peculiarly 

 obnoxious odor. None of the higher parasitic fungi were found in the 

 affected plants whicli could in any way have caused the disease, and at 

 the time of rotting tlie only other organisms associated with it were 2 

 species of scavenger beetles. 



Numerous successful inoculations were made. The author conducted 

 a series of cultures in order to isolate the bacteria. He found 2 species 

 in abundance. The most abundant species constituted about two thirds 

 or three fifths of all the individual specimens. They weie always 

 motile, and in doubles, never in chains. In size and behavior the spe- 

 cies resembled Bacterium termo. With it occurred small numbers of a 

 larger bacillus, often in short chains, but generally in doubles, which 

 measured about 0.0042 in. in length. In shape it was not unlike the smaller 

 bacteria, with short, thick, rounded extremities, and staining solidly. 

 These 2 species were always abundant in the agar cultures, the bacillus 

 producing a Avhite growth and the bacterium a more rapid yellow 

 growth. 



A few tests which were made in the fall of the year with cultures of 

 the 2 species of bacteria were without decisive results. Since the sum- 

 mer of 1889 opportunities have not been offered for the further study 

 of this disease. 



The brunissure of the grape, F. Debray {Gompt. Bend., 119 {1894), 

 JVo. l,2)p. 110,111). — During the month of May this disease appeared 

 in many of the vineyards about Algiers. The temperature had been 

 unusually cold, accompanied by fog, and there had been frequent heavy 

 rains. The vines developed* very slowly and their leaves were much 

 smaller than usual. In some regions the young shoots were greatly 

 elongated, and while the shoots themselves were not attacked their 

 lower leaves were diseased, the upper ones remaining sound. Most 

 plants lost their shoots by their becoming completely dried up. 



