334 



THE TROPICAL AGRICULTURIST. [Nov. i, 1886, 



THE MOUSE PLAGUE OF BRAZIL. 



lu the colony of Lturen^o, Brazil, in the mniitbs 

 of May and June, 1876, mice suddenly appeared ia 

 enormous numbers. They invaded the ujaizo fields 

 in such great numbers that the corn seemed literally 

 alive with them, destroying in a few days everything 

 that was edible; and where but a short time before 

 bushels of grain might have been harvested, not an 

 ear remained ; and the noise produced by their nib- 

 bling and climbing was audible^ for a considerable 

 distance. After the corn-fields were devastated the pot- 

 atoes next received their attention. Only the largest 

 were eaten in the ground, such as were transportable 

 were carried away and hidden in hollow trees, or 

 other retreats, for future use. Gourds and pump- 

 kins, even the hardest, were gnawed through and 

 eaten. Of green food, such as clover, oats, barley, 

 not a leaf was left standing; even weeds were cut 

 dowh and the inner parts eaten out. In the house 

 the struggle for existence of these long-tailed invaders 

 was truly amazing. In many of the dwellings hun- 

 dreds were killed in a single day. The cats could 

 contribute but little aid fighting such a plague, for 

 not only weie many of the mice so large that it would 

 have been an unequal contest, but by their great 

 number they drove 'the cats actually from the houses, 

 not to return until the plague was passed. Nothing 

 except what was composed of iron, stone, or glass, was 

 spared from their destructiveness. Furniture, clothes, 

 hats, boots — everything bore the traces of their teeth. 

 They gnawed the hoofs of the cows and horses in the 

 stables, literally ate up fatted hogs and often bit away 

 the hair of persons during sleep. They penetrated 

 all apartments, and gnawed, their way through boards 

 and walls of houses. Ditches that were dug about 

 granaries did not sufiice;the mice would chmb over 

 each other in some corner or other and thus reach 

 the top. The foregoing account of one occurence in 

 Louren(;o will suifice to show to what an extend the 

 plague reached. The same proviuce had suffered 

 similary in 1843 and in 1SC3, and in all probability 

 will again in 1889. Similar plagues, though far less 

 in extent, have occured in Europe, in which the field- 

 mice unaccountably appeared in greatly increased 

 numbers. One may well- think . what would be the 

 result were these little, almost insignificant creatures 

 everywhere in such wise to take the ascendancy. 

 When one considers that on an average of every one 

 or two months from five to eight young arc born, 

 and that these young become mature in a few months 

 themselves, he will not be surprised to know that a 

 single pair of common field-mice, in the course of a 

 single summer, would increase to 28,000 individuals. 

 Could all the conditions which now keep them in 

 check be removed, every living thiag upon the earth 

 would be consumed in a haif-dozen years. — Science. 



A NEW OPENINa FOE THE UTILISATION OF 



THE SWEET POTATO AND YAM IN THE WEST 



INDIES. 



The root crops, often termed "bread kind," associa- 

 ted with the above plants are largely used in the 

 West Indies for food purposes. The sweet potato 

 {Butatai edalis) is the main food crop at Barbados, 

 where yam is little known, whereas at Jamaica the 

 converse is the case, the yam {Dioscoroca) being very 

 largely grown all through the interior hills, while 

 the cultivation of the sweet potato is confined 

 to a few places in the lowlands. Since the large 

 emigration of negroes to the Isthmus of Panama 

 there has arisen a considerable trade in yams between 

 Jamaica and Colon, to the manifest advantage, in 

 present cash returns, of the former country. Un- 

 fortunately, the cultivation of yams entails the cutting 

 down of forest year by year, as good yams seldom 

 do well, in the manner cultivated at .Jamaica, except 

 by the "rotation of land" — a peculiar negro mode of 

 interpreting the European idea of " rotation of crops." 

 . Hence it is not very desirable, from a general economic 

 point of view, to extend or encourage the cultivation 



of yams. With the sweet potato, however, it is differ- 

 ent. This tuber can be grown without the sacrifice 

 year by year of valuable virgin forest, and it is, in 

 many respects, a crop well adapted to all the lowlands, 

 not only of Jamaica, but also of the West Indies 

 generally. 



Besides being utilised directly for food purposes, it 

 would appear that a new demand is likely to arise 

 for the tubers of the sweet potato in connection 

 with the production of the alcohol. The first notice 

 of the sweet potato being utilised in this manner 

 appeared in a report to the Foreign Office given by 

 Consul Hertslet on the trade and commerce of the 

 Azores for the year 18S-1. 



Owing to a variety of causes, it appears that cul- 

 tivators at St. Michael's and other islands of the 

 Azores, who had hitherto looked upon oranges as their 

 staple production, were so disheartened by low prices 

 and the diminished crops yielded by their trees, that 

 they resolved to clear their land of everything and plant 

 it afresh with sweet potatoes. The whole of the crop 

 thus raised was used in the preparation of alcohol. 



During the year 1884, 1,326 pipes of alcohol, of 

 the value of £40,588, made from sweet potatoes, were 

 exported from Azores to Lisbon ; and, as will be in- 

 cichmtally shown later, the trade has assumed still 

 larger proportions. 



For the imformation contained in this article we 

 would mention at the outset that we are indebted 

 to Mr. D. Morris, late Director of public Gardens 

 and Plantations, Jamaica, now of the Royal Gardens, 

 Kew, who has obligingly placed it at our disposal 

 for the use of West Indian planters. 



Encom-aged by the success of the enterprise at the 

 Azores, it appears that an enterprising French chemist. 

 Monsieur A. Ilalu, having much experience in chemist- 

 ry, as connected with distillation, and possessing 

 extensive relations with the West Indies (Martinique), 

 has taken out patents: — (1) For utilising as a commer- 

 cial and industrial substance sweet potatoes and yams 

 by means of desiccation and conversion into tlour ; 

 and (2) for distilling alcohol from the above flour. 



In relation to the ordinary or Irish potato, white 

 beetroot, and maize flour, sweet potatoes possess an 

 alcoholic richness of 1.5-50 per cent as comijared with 

 8 and 9 per ctnt in the Irish potato, and 4 and 5 

 per cent in the beetroot. The value of raw sweet 

 potato for distillation, and its superiority, both as to 

 quantity and quality, over other subst;iuces, has been 

 for some time known and recognised. The ditficulty 

 has been in extracting the alcohol on the spot ; 

 added to this, there is the danger attending its 

 exportation, for it is impossible to prevent leakage, 

 and the vapour of alcohol at 95^ Fahr. in hot clim- 

 ates is said to be inflammable. Alcohol, therefore, 

 is assumed to be a dangerous cargo. As alcohol cannot, 

 it is supposed, be made on the spot and exported 

 to J5urope, M. Ralu's patents aim at the preparation 

 of sweet potato flour in the West Indies, from which 

 afterwards the alcohol may be distilled and utilised 

 in Europe. 



As already noted, one establishment for distilling 

 alcohol from raw sweet potato exists at the Azores, 

 and we gather that since it began work it has doubled 

 its plant, and all the alcohol it produces is sold in 

 advance at Lisbon, where it is used for the fortification 

 of wines. M. Ilalu says : — " The alcohol of which we 

 have specimens is superior in quality to the best 

 marks of France. The distillery obtains 12 per cent 

 {I.e., 12 litres of alcohol at 100^ per 100 kilog. of 

 sweet i)otato) of alcohol. We have experimented 

 with the sweet potato of Algeria. They give Hi 4-10 

 litres of alcohol per 100 kilog. The sweet potato of 

 Martiniciue and Brazil have given 15 litres. There 

 is here, therefore, a very rich material for distillation. 

 Ordinary potatoes yield only 3 litres of alcohol per 

 100 kilog." 



The objects sought by M. Ralu's patents involve 

 the extensive cultivation of the sweet potato in the 

 West Indian Islands, its desiccation by means of 

 fruit driers, its reduction into a meal, and its ex- 

 port to Europe, where an almost unlimited demand 

 exists for sweet potato meal for distilling purposes. 



