230 TEXT-BOOK OF FUNGI 



time centres of disease, from which material for infection 

 spreads in every direction. To suppress this possibility, 

 the outcome of sheer neglect or thoughtlessness, drastic 

 legislative measures are in force in some countries. 



The above statements must not be interpreted as a 

 tirade against legislation, but simply to indicate some of 

 its weak points, as at present administered, and at the 

 same time to prevent too bitter disappointment on the 

 part of those who are inclined to expect through legis- 

 lation, however strictly enforced, any marked decrease 

 in the number or intensity of plant diseases caused by 

 fungi. 



Several definitely proved examples of modes of dis- 

 seminating disease have been indicated which are obviously 

 outside any possible legislative code that could be formu- 

 lated. These, however, by no means exhaust the list of 

 cases. The transportation of straw and forage is a whole- 

 sale means of diffusing diseases of cereals and grasses, as 

 the spores of many of these fungi suffer no injury in even 

 passing through the alimentary tract of an animal. Again, 

 no law would insist on a man collecting and burning all 

 diseased potatoes or turnips met with in a field, even if in 

 a condition to be collected. 



In some instances a plant that has been introduced to a 

 new country has been attacked by an indigenous fungus. 

 The coffee disease in Ceylon is a case in point. Soon 

 after its introduction it was attacked by a fungus called 

 Hemileia vastatrix, which resulted in the cessation of coffee 

 cultivation in the island. From this centre the disease 

 spread contemporaneously with the cultivation of coffee, 

 and has practically rendered unremunerative this branch of 

 industry throughout the old world. 



