IM.ANJ- DISKASES AND FUNC'.l. 27 



'J"he remaining six seeds, when removed from the soil, were decayed 

 and noisome. 



In another experiment, eight seeds were placed on blotting 

 paper, moistened with distilled water, and covered. A duplicate set 

 were similarly watered with a solution containing bacteria from a 

 decaying cucumber. The first series all germinated with their usual 

 vigour, while those which came in contact with the bacterial germs 

 failed to germinate, and soon decayed. 



" The pure virus was next introduced into the growing stems and 

 green fruits of the tomato, and in both cases quickly produced a 

 decay that caused the stems to fall, and the fruit to become a watery 

 mass enclosed by the skin, similar to the cucumber from which the 

 bacteria were taken for inoculation. At the time of the experiments 

 some boxes of young tomato plants were close at hand, and into the 

 centre of one of these a decaying cucumber was placed. In six hours 

 some of the stems of the tomato plant, six inches in height, had 

 rotted off close to the ground, where the liquid from the decaying 

 fruit had come in contact with the young plants. In ten hours all 

 the plants in the vicinity of the decaying cucumber were destroyed." 



This account seems to be rather conclusive, especially when inde- 

 pendently and collaterally supported by evidence given by other 

 observers in respect to other plants, having similar results. From 

 the report of the New York Agricultural Station for 1887, we gather 

 that bacteria are found in great abundance in actively blighting 

 tissues of "pear blight," so as to be easily demonstrable to the naked 

 eye, and occur in less abundance in proportion as the disease is less 

 active. This disease may be introduced into healthy tissue by 

 inoculation with germs from diseased tissue. It is communicated 

 with equal certainty when the germs are separated from all accom- 

 panying juices of the diseased tissue, by a series of fractional cul- 

 tures. It is not communicated by the juices of the disease after the 

 germs are removed by filtration. 



Without following this part of our subject further, it is essential 

 that we indicate some mode of escape or amelioration of this class of 

 plant diseases. It should be unnecessary to insist upon some similar 

 line of action to that pursued in similar diseases in man or animals. 

 In the first place there must be a scientifically accurate diagnosis of 

 the disease, and this must be followed by the special remedy which 

 has been proved effectual in that class of disease. There is no specific 

 for plant disease, as there is none for animal disease. We can point 



