TRANSACTIONS. 69 



from the growth of a micro sopic parasitic vegetable, or 

 whether they are produced bj an insect, as in our Florida 

 orange, is matter of dispute, and it is not improbable that 

 both causes are at work in diiferent localities. The silk- 

 worm has always been liable to many disorders, but a new 

 disease has made its appearance in France, and excited a 

 good deal of alarm among the silk-growers. It has no very 

 distinct symptoms or characteristics, and appears to con- 

 sist rather in a general degeneracy of the species arising, 

 as some conjecture, from the want of crossing, or breeding 

 in and in, as it is technically termed. It is, however, too 

 recent to have been yet thoroughly investigated. 



From the prevalence of these evils we may draw the 

 important lesson, that sound policy requires a considerable 

 range in the objects of rural industry, in order that the 

 failure, temporary or continued, of any one branch of hus- 

 bandry, may not produce the ruinous effects, which have 

 resulted in many European countries from a too exclusive 

 devotion to a single agricultural pursuit, and the conse- 

 quent dependence of a whole population on the contingen- 

 cies of one method of earning its bread. 



Having thus viewed the general surface and most strik- 

 ing physical characteristics of several of the principal 

 continental countries, let us look at some points of their 

 rural economy a little more in detail, and see what is most 

 worthy of imitation in their public improvements and their 

 private husbandry. I cannot of course on this occasion 

 go into minute particulars, or notice all the specialities, 

 which one having time and adequate motive to devote 

 himself to individual fields of agricultural and industrial 

 inquiry would bring out, and I must content myself with 

 selecting a few obvious points of comparison, and which 

 seem to me interesting as evidences of our superior pro- 

 gress in some particulars, or on the other hand suggestive 

 of improvement in our rural life. 



A striking point of difference in the industry of Europe 



