CULTIVATION OF JALAP. 347 



during the night. In the daytime from 60 to 75 Fahr. is their 1867. 

 almost daily warmth. Around Cordova the plant will not suc- 

 ceed, the climate being too warm. I would advise you to plant 

 some of the tubers out in the free air, treating them like dahlias, 

 that is, to take up the roots in October, and plant them again in 

 March or April. Although the plants may not flower or ripen 

 seeds, the tubers will grow in size, and what is more important, 

 will multiply underground ad infinitum. If jalap-roots so far 

 have failed in Europe, it is because they have been treated as 

 hothouse plants." 



Having these data regarding the climate and soil which are Soil and 

 natural to the jalap-plant, we must next consider what regions 

 offer conditions sufficiently similar to render the culture of the 

 plant probably successful. It is plain from the accounts I have 

 quoted that a humid climate having a temperature rising in sum- 

 mer to about 75 F. and sinking in winter to the freezing point 

 is that which the plant naturally affects ; and this is confirmed 

 by the fact that the plant thrives perfectly well in the open air 

 during the summer months, in gardens in the south of England, 

 but that it will not endure unprotected the severe frosts of 

 winter. Whether the great altitude above the sea-level at which 

 it occurs in Mexico, is an indispensable condition for its com- 

 plete development, is a point on which we have no infor- 

 mation. 



In Cornwall and in some localities in Devonshire, as well as Suggestions 

 on the southern side of the Isle of Wight, it is probable the 

 jalap-plant would thrive in the open ground as a garden-plant 

 during the whole year, and it is very desirable that experiments 

 should be made to determine this point. In Madeira it would 

 probably also succeed well if planted in situations sufficiently 

 elevated. 



But if it be necessary to select the situation in the British 

 dominions which for climate and elevation above the sea-level 

 presents conditions most nearly resembling those of the jalap- 

 yielding region of the Mexican Cordillera, we must, I think, 

 look to some localities in India ; and of those that can be named 

 the Neilgherry Hills in the Madras Presidency offer perhaps the 

 greatest combination of advantages for attempting the culti- 



