AGRTCFLTUKK AT THE AMEEICAN ASf^OCIATION. 531 



A paper hv L. K. floiics and L. P. Spra^'iie, (Mititlcd IMiim I)lio-ht 

 Giiised by the Pear P)lis4-lit Oroanisin, was read In' L. K. flones. The 

 blight was conlined to young- plum twigs from which the pear blight 

 organism {Baclllmamylovorus) was isolated. The inoculation of green 

 pears with portions of the diseased plum twigs was found a very satis- 

 factory method of investigation. Organisms isolated from both the 

 plum and pear were grown in a series of artificial cultures and found 

 to behave alike in every respect. Typical cases of pear blight were 

 produced by inoculation with the bacillus obtained from plum twigs. 

 The typical plum l)light, howevei', was not secured b}^ inoculation. 

 The organism was l)elieved to gain access to the young twigs by way 

 of the axillar}^ buds. If allowed to develop unhindered in plums, it 

 was suggested that the organism may acquire increased virulence toward 

 this host. 



E. F. Smith called attention to a bacterial disease of Japanese plums 

 in which both leaves and fruit are afiected. The organism was found 

 to enter through the stomata existing on the fruit and leaves. The 

 disease was first reported from Michigan, and although under investi- 

 gation for a number of years, a single organism has always been found 

 present. In one orchard the fruit of four-fifths of the Hale plums 

 were afiected, and a second variety. Wickson, was attacked to a less 

 extent. The organism, entering through the stomata of the fruit, 

 develops abundantl}^ breaking down the tissues and producing pecu- 

 liar diseased areas, which were described at considerable length. On 

 the leaves the organism causes a shot-hole effect, the dead portions fall- 

 ing out. This organism has ])een isolated and cultivated, and inocula- 

 tion experiments prove it to l)e the cause of the disease. It is described 

 as Pseudomonm pi'iou, n. sp. In a second paper the author offered 

 proof that P. stewartl is the cause of the sweet corn disease occurring 

 on Long Island. This disease may be first recognized from the char- 

 acter of the inflorescence, the male spikes giving the first indication of 

 disease. These take on a peculiar white color, followed later by the 

 wilting of the corn, which is said to characterize the disease. The 

 author isolated and cultivated the organism, and by means of inocula- 

 tion has secured characteristic symptoms of the disease in at least 75 

 per cent of his infections. 



L. K. Jones gave the results of studies of cytohydrolytic enzyms 

 produced by the soft rot bacteria, BaciUdS carotoconis. The enzym 

 was separated from the living organism by filtration, sterilizing by 

 heating, by the use of phenol, thymol, or formalin, and b}' precipita- 

 tion. Detailed studies were made with the enzym secured, and prac- 

 tically no diastatic action was o])served. 



W. A. Orton, in a paper read before Section G, described a disease 

 of mulberry fruit which is reported from Georgia, Alabama, and 

 Mississippi. Often as much as 50 per cent of the fruit is afiected. 

 The symptoms are peculiarly eidarged portions of the aggregated 



