Naturalisation in Extra- Tropical Countries. 511 



writer of this work, have proved, that as a winter-crop the potato can 

 also yet be had in Central Australia. In frostless regions of Aus- 

 tralia new potatoes can be obtained throughout the year. Even in 

 the lowlands of Jamaica under ordinary culture select potatoes have 

 been obtained weighing over ^ Ib. [H. C. Munn] . The cultivation of 

 Potatoes is on the increase in India ; they are generally planted at the 

 end of the rainy season, after the Rice has been harvested ; irrigation 

 is mostly resorted to [Dr. G. Watt]. In Norway, it can be grown 

 as far north as 71 7' [Schuebeler]. In the Australian Alps reared 

 successfully to 4,800 feet [J. Stirling]. From some varieties of 

 potatoes three crops may be obtained within a year in regions free 

 from frost. In rich coast-lands of Victoria as much as 14 tons of 

 potatoes have been taken from an acre in a single harvest. As a 

 starch-plant, the potato interests us also on this occasion particularly. 

 Prof. J. H. Gilbert points out, that although richly nitrogenous 

 manures promote much the growth of the Potato-plant, yet the tubers 

 get mainly enriched in starch only. Seaweeds can be used as manure 

 for the Potato-plant. Water, in which potatoes have been boiled, 

 serves against slugs and aphides [H. G-. Pratt]. Considering its 

 prolific yield in rich soil, we possess as yet too few factories for 

 potato-starch. This starch, irrespective of its many other uses, is 

 preferentially chosen for calico-printing. The average yield is 10 per 

 cent. Great Britain imported, in 1884, about 14,000 tons of dry 

 yeast, for the manufacture of which potato-starch is largely used, at 

 a value of 777,000. The starch, by being heated with mineral acids 

 or malt, can be converted into dextrin and dextro-glucose for many 

 purposes of the arts. Dextrin, as a substitute for gum, is also obtain- 

 able by subjecting potato- starch in a dry state to a heat of 400 F. 

 Alcohol may be largely produced from the tubers. The berries and 

 shoots contain solanin. Baron von Liebig remarks, " So far as its 

 foliage is concerned, it is a lime-plant ; as regards its tuber, a potash- 

 plant." Langethal says, " It surpasses in easy range of cultivation 

 all other root-crops ; its culture suppresses weeds and opens up the 

 soil, besides preparing the land for cereals." Seeds of the potato- 

 berries should be sown in adapted places by explorers of new countries, 

 provided the natives can be made to understand that the berries are 

 poisonous. The most formidable potato-disease of the last fifty 

 years, from the Peronospora infestans, seems to have originated from 

 the use of objectionable kinds of guano, with the introduction of 

 which the murrain was contemporaneous ; along with this Fung the 

 Fusisporium Solani works almost constantly its mischief also ; to 

 destroy their hibernating spores all vegetable remnants on potato- 

 fields must be burnt [W. G. Smith]. Prof. Max. Cornu recommends 

 syringing with a solution of sulphate of copper (1 to 200) against 

 Peronospora infestans. The application of the "Bouillie Bordelaise" 

 against the Potato-fungus is also very advantageous, but the saccharine 

 Copper-Lime liquid is preferable to the ordinary Bordeaux mixture, 

 as it is less apt to be washed off by rain [Perrett, Girard]. The 

 foliage of potato-plants, when thickly placed under trees or shrubs, 



