-7- 



thls particular consignment had been at sea for days, and on arrival 

 in port of the inporting country was condemned hy the authorities 

 for being diseased; the sample, however, had teen obtained else- 

 where. Unless such a certificate affords guaranty for the 

 inspection of the shipment to which it applies at the port of 

 exit, stating that the vegetable matter has been found free from 



disease and has been officially sealed in the ship or car, it 

 cannot practically serve its purpose. In addition, I t^uestion 

 again the possibility of certifying 'tn'y kind of vegetation tobe 

 free from certain diseases. It has been my experience in Canada 

 to be able to certify when a shipment is diseased - but never the 

 contrary with an entirely free conscience. 



This reference introduces the problem of "inspection at the 

 ports or ports of entry'^. The United States and Canada have bean 

 seriously threatened of late years by the introduction from Europe 

 of two very undesirable diseases. White Pine Blister Rust and 

 Potato Canker. In a bulletin recently published by the United 

 States Department of Agriculture, Division of Forest Pathology, it 

 is stated: "Inspection cannot defect affected trees except those, 

 which already have developed swellings or fruiting bodies. The 

 Blister Rust vegetates in the bark tissues of pine for a number of 

 months before anyexternal signs of its presence are visible. This 

 period of incubation is of uncertain length, but apparently varies 

 from about one year to several years. Dmring this time no in- 

 spection, hovvrever, thorough, can detect the (disease." 



It will be easily understood rhat the consequence to Canada 

 and the United States of America would be of the establishment 

 of this disease, tehich is correctly considered one of the most 



