72 Massee : The Action of Bacteria on Higher Plants. 



the introduction of the necessary Bacteria to the previously 

 sterile soil. 



Such phrases as 'clover-sick,' 'beet-sick,' etc., applied to 

 land that fails to produce a crop, has been proved to be owing- 

 to the temporary absence of the specific Bacterium necessary for 

 the growth of the clover or beet, and that when this organism 

 is reinstated vigorous growth of the crop is assured. 



In concluding my remarks on soil Bacteria, it may be stated 

 that careful researches have proved the presence of these 

 organisms in fertile ground, in both tropical and temperate 

 parts of the w^orld ; in fact, the presence of vegetation implies 

 their presence also. 



On the other hand, remembering that sourness, excess of 

 water, or exceptional compactness of the soil prevents the 

 indispensable Bacteria from performing their functions, it only 

 remains for the practical man to modify such detrimental con- 

 ditions, and thus render fertile many thousands of acres of land 

 which at the present moment will not support a goose per acre. 

 It is not necessar)' to go outside England to demonstrate the 

 truth of this statement. 



Having thus far held a brief for those Bacteria who un- 

 consciously promote our welfare in the ways indicated, it is 

 equalh^ important to call attention to other members belonging 

 to the same group, whose actions, except to the person whose 

 frame of mind enables him to see 'good in everything,' will be 

 viewed with suspicion. I allude to those Bacteria causing plant 

 diseases. 



Until quite recently it was generally held that the vegetable 

 kingdom was exempt from the prejudicial influence of Bacteria. 

 This idea has unfortunately proved to be wrong, recent inves- 

 tigations, mainly conducted by -American scientists, having* 

 definitely proved that not a few epidemics of a serious nature 

 attacking cultivated plants are caused by Bacteria. Among 

 such may be enumerated the following, which, along with 

 others, have been observed in this country : — 



Bacterial Disease of Potatoes. 



This disease so far as Britain is concerned, was first recorded 

 from Easingwold, Yorkshire, where it was quite prevalent during 

 1902. In the United States it is a very destructive disease, 

 attacking potatoes, tomatoes, and egg-plants. The earliest 

 sign of attack is the sudden wilting- of the leaves, followed by 

 a shrinking- of the haulm, which soon droops and dies. If 



Naturalist, 



