40 YALE AGRICULTURAL LECTURES. 



the flowers fall without setting fruit, while in the hot and damp 

 climate seed-balls set freely, but, with the whole plant, fall a 

 prey to mildew. 



The cause of disease Mr. Goodrich believes to be the facility 

 with which a weakened cellular structure will pass into fermen 

 tation, in presence of albuminous matter. For a remedy he 

 advises to mow off, or pull up the tops, when it is evident that 

 the weather will not speedily change for the better, but even 

 this will be unavailing in some cases ; so that to my mind all 

 this goes to show that our only remedy is to cultivate as well 

 as we know how, choosing new and hardy sorts of potatoes, 

 planting early, and trust to chance for the rest. 



The mowing of tops has been tried over and over again, with 

 sometimes success and sometimes the reverse ; and so have a 

 thousand other remedies, each of which has in turn been pro 

 claimed a specific. A prize-essay in the Royal Society's Jour 

 nal for 1858, gives us to understand that deep planting is the 

 true and only remedy ; and yet I have planted deep and so 

 have thousands of others and yet lost a crop. Mr. Goodrich 

 has spent years in close observation, and accumulated a fund 

 of information, but I venture to say that even he has not yet 

 explained this mysterious disease, its origin and antidotes, so 

 clearly that he who runs may read. 



This morning Mr. EATON spoke briefly about flowers and 

 fruits, showing how the pollen, or yellow dust of the flowers, 

 acts on the ovules or rudimentary seeds ; causing them to de 

 velop into seeds containing an embryo, and capable of grow 

 ing up into new plants. 



From this he went on to the subject of hybridization, and then 

 of grafting. Grafting has been practically known for many cen 

 turies in fact since the world was young ; but the theory was 

 left to botanists to discover. Between the bark and wood are 

 what are called cambium layers, or the growing part of the 

 tree, the one which possesses the most active vitality. Un- 



