POTATO DISEASE. 293 



further investigation. I was informed last summer by a 

 neighbor that he had cultivated a certain early variety of the 

 potato upwards of twenty years in succession for the market, 

 and had not observed that they have been affected with the 

 malady. Many experiments have been made which have 

 resulted in favor of early planting. This fact might be 

 explained by supposing that the plants of an early crop arrive 

 at the flowering period when the weather and season are favor- 

 able to vigorous health and development, and at that stage of 

 their growth when the disease is most likely to affect them. 

 Hence we may explain why the early planted crops are more 

 likely to produce balls and to ripen their seeds. 



The following experiments might be made with the view of 

 obtaining information under this head: — Plant one field with 

 potatoes forced in a hot-house calculated for the earliest possi- 

 ble maturity. Plant another field as early as practicable with 

 potatoes which have not been forced. Plant a third field with 

 the same sort at a late period. It would be advisable to watch 

 the effects of the forcing process upon the health of the product. 

 Such a process might serve to aggravate the tendency to disease. 

 A considerable amount of information in regard to the effects 

 of early planting might be gathered from the experience of 

 market gardeners. 



VIII. Some advantages may be found to result from plant- 

 ing the potato in succession after certain specified crops. Some 

 kinds of plants may affect the soil favorably, and others unfa- 

 vorably with respect to the healthful growth of the potato. 

 We know that this principle of rotation must be observed in 

 planting the most of our crops, if we would secure both a 

 healthy and abundant product, and the knowledge and observ- 

 ance of certain rules of rotation constitutes an important part 

 of the science and practice of agriculture. We may, therefore, 

 not unreasonably expect to reap some valuable information 

 from experiments of this class, relating to the potato culture. 

 It is highly probable that the soil, immediately after a certain 

 crop, may be favorable to a healthy product, and that these 

 effects may be sufficient to make it expedient to raise the potato 

 invariably in succession with some other vegetable, — it may be 

 some one of the cereals, it may be clover or pease, or it may be 

 after a fallow. 



