292 MASSACHUSETTS AGRICULTURE. 



All the tubers of such plants should be rejected as seed pota- 

 toes, which should be carefully selected from the product of 

 those vines which matured their bulbs. This may be another 

 expedient for increasing the chances of a healthful crop, as well 

 as for increasing its abundance. 



VI. Another course of experiments should be made to 

 ascertain the different degrees of liability to the disease that 

 exists in the various sorts. The varieties of the potato are 

 almost infinite in number. These, it is well known, differ 

 exceedingly in quality, and the best varieties commonly yield 

 the least abundant product. Some sorts are hardly worthy of 

 cultivation, except for swine. It is not probable that all these 

 are equally subject to the malady. Not only ought this point 

 to be ascertained by experiment, but the different varieties 

 should be classified, in order to determine whether the disease 

 is milder or otherwise in those of a particular character ; in 

 those for instance, of a certain shape or color. We should 

 learn whether the white-meated sorts are more liable to be 

 affected than those with yellow, red or blue meats; and whether 

 the color of the meat has any connection with a constitutional 

 liability to the disease or exemption from it. I think I have 

 noticed that the yellow-meated kinds arc not so badly affected 

 as those with white meats ; but the former are not so good for 

 the table as any of the other sorts. If, however, a superior 

 degree of exemption from disease be connected with this yellow 

 hue of the pulp, there is good reason for endeavoring to 

 improve the quality of the yellow kinds, by raising seedlings 

 from them. 



It is not unlikely that there may be some constitutional pre- 

 disposition to disease which is greater not only in some partic- 

 ular sorts, but perhaps in those of certain color of the pulp ; — 

 as in the human system there is a constitutional liability to 

 pulmonary complaints in persons of a peculiar complexion. I 

 would, therefore, experiment not only with individual varieties, 

 but with classes, — carefully noting the liability of the white 

 meats compared with the yellows, the reds and the blues, and 

 learn whether any color, on the average, is more or less subject 

 to disease than the others. 



VII. The comparative advantages of late and early plant- 

 ing have not been overlooked, and they are worthy of still 



