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intended for < seed.' It must be admitted that the ^ results 

 obtained up to the present have not been very encouraging, the 

 time being too short to remove the deterioration which has been 

 established by a prolonged period of more or less intensive culti- 

 vation ; nevertheless certain points have been noted which may 

 prove to be of value to future experimenters. 



Degeneration appears to be due mainly to the vegetative method 

 of reproduction commonly followed. Even in the case of seedlings, 

 the parents of these must, at least, be closely related. 



Imperfect development of the fibro-vascular system is mainly 

 due to the desire to obtain a potato with an even surface, that is, 

 to abolish the sunken 4 eyes ■ of the older type of potato. Selec- 

 tion has accomplished this point, but at the expense of germinating 

 power. In the old type of tuber the i eyes' were depressed to the 

 level of the fibro-vascular ring, which supplied food directly to the 

 sprouts springing from it. In the modern potato, resembling the 

 surface and contour of an egg, the * eyes ' have dwindled to a 

 mere suggestion of such, in other words the cortical portion of the 

 tuber, or the portion outside the vascular ring, has increased in 

 thickness, but the branches that connect the ' eyes ' with the 

 vascular ring from which they have been raised, are too often 

 merely rudimentary, and fail to convey food to the sprouts. 



On the whole, the failure of many otherwise excellent varieties 

 of potatoes to grow vigorously is due rather to a lack of diastase 

 than to morphological imperfections. This, as already explained, 

 is manifested in the persistence of the starch in a solid form. 



The nearest approach to a return to normal conditions has been 

 met with in the case of potatoes grown for three years in succession 

 on the same patch of sandy ground and without a trace of manure 

 of any kind. The original 4 sets • of a highly prized modern type 

 were each reduced to the condition of being able to produce only 

 one sprout at the apical end. The product of the third generation 

 formed vigorous sprouts from every part of the tuber, thus proving 

 that abandonment of all forcing or selective tactics enables the 

 plants to regain their power of producing diastase. This result, 

 however, was at the expense of all those points that have cost the 

 cultivator so much time and labour to secure ; the crop was small, 

 the tubers few in number and only of average size and the 4 eyes ' 

 were considerably depressed. 



Superphosphate increased the amount of diastase to a much 

 greater extent than a liberal dressing of farmyard manure. 



Light favours the production of diastase much more than 

 darkness, also a greater amount is produced in a high than in a 

 low temperature. 



A very interesting discovery on this point was made by 

 Mr. Watson, Curator of the Royal Botanic Gardens. Some tubers 

 that had refused to produce sprouts when placed under the 

 most favourable conditions available to the ordinary grower, were 

 placed in^ one of the forcing pits having a temperature averaging 

 about 70° P. and were not covered. In due course sprouts 



