SCIENCE-GOSSIP. 



289 



FUNGOID PLANT DISEASES. 



By John T. Carrington. 



A MONG the inexorable laws of nature that 

 ■^^ govern the maintenance of the balance of 

 life, disease is one of the principal factors in 

 reducing the numbers of any especial species which 

 is unduly asserting itself in increasing numbers. 



world with apparently cruel severity. If, however, 

 man could sufficiently understand their effect upon 

 the future condition not only of the species attacked, 

 but also of the surrounding inhabitants of the region 

 affected, he might think less of the inconvenience 



Scene in a Bav.\ri,\n Forest. 



In the foreground a living beech-tree with seven sporophores of Polyporus join cut ariin. 



{From " Discast's of Plants," published by Longmans & Co.) 



The most potent forms of disease, whether among 

 plants or animals, are caused by fungoid or 

 other cryptogamic parasites. To these sources 

 may be traced the various epidemics which 

 occasionally sweep large districts of the habitable 



April, 1897. — No. 35, Vol. III. 



to the individuals attacked, or of his own. Nature 

 by its forces seldom exterminates the fittest 

 inhabitants, except for the general good, and it 

 is usually the weaker members of the species 



attacked that succumb. In maintaining the 



