Vol. XVIII. No. 453. 



THE AGRICULTURAL NEWS. 



27.9 



HOG CHOLERA LOSSES DECLINING. 



Since 1913, when the United States Department of 

 Agriculture began work to control hog cholera, the dreaded 

 disease has become less and less destructive each year. A 

 force averaging 16.5 federal veterinarians has been maintained 

 working in cooperation with State authorities in charge of 

 quarantine and other regulatory measures necessary for the 

 success of control work. During the fiscal year 1918, more 

 than .5,.500,000 hogs were inoculated with antihog cholera 

 serum, and more than i,200 farm.s, found to be infected with 

 cholera, were cleaned and disinfected under supervision of the 

 department verterinarians. 



Altogether representatives of the department visited 

 more than l,.oOO farms to investigate reported out breaks, 

 to apply preventive measures, and to clean and disinfect 

 premises. How great a menace hog cholera has been to the 

 nation's swine industry may be judged from the accepted 

 estimate that 90 per cent, of hoes lost from all ailments die 

 from cholera. In 1918 the death rate of swine from disease 

 was placed at 42-1 per thousand. Thus the loss was slightly 

 above 4 per cent, for the United States, the lowest on 

 record, according to the department's figures. (From the 

 Caiifornia Cultivator.) 



CONTROLLED FERMENTATION OF 



TOBACCO. 



One of the principal difticulties of tobacco pro- 

 duction is not in the growing, nor in the curing, but 

 in the fermenting. This was found to be the case in 

 St. Kitts and in other small West Indian islands 

 which at one time endeavoured to establish a tobacco- 

 growing industry. Perhaps the following information, 

 taken from the International Review of the Science 

 and Practice of Agriculture, may lead to the estab- 

 ilishment of co-operative tobacco fermentation factories 

 in places where the cultivation of the crop could be 

 carried on by small growers: — 



The series of tobacco fermentation experiments carried 

 out for several yeirs by the Vorstenlanden Tobacco Experiment 

 Station (Dutch East Indies) has led to the construction of 

 a building where tlie mounds of tobacco can undergo 

 continuous fermentation without handling. 



Satisfactory results were obtained. The tobacco 

 fermented is of very good quality. The building is composed 

 of three rooms 4 metres wide, 4~.5 metres long and 3 50 

 Metres high internal measurements. The double walls are 

 hollow, but closed here and thi re by brickwork which 

 supports the walls. The middle walls, which are very thick, 

 isolate the rooms sufficiently from one another. Ijighting 

 is obtained through three small windows 2.5 x 50 cm. 



As the temperature is lower near the windows, it is 

 taken in the centre of tlie room by means of electric 

 thermometers. The rooms are closed by double doors, the 

 outer one of wood, the inner one of eternite. The rooms 

 ' are roofed by slabs of eternite, above which there is an 

 insulating layer of rice husks covered by planks; the 

 ceiling is supported by wooden supports. 



Gis pipes, 5 cm. in diameter, are used for heating. In 

 each room there are rings of tubes running along the walls 

 provided with a tap for regulating the temperature and 

 arranged in such a way that their lower end is near the 

 wall of the machinery room. At that point there are also 

 drainage pipes provided with taps, so that the wnter of 

 condensation can be drained a«ay to tbe outside. In fact, 

 the water must be drawn off regulaily or the pipes will 



not heat. Tubes, 25 cm. in diameter, connect the heating 

 pipes to the boiler. The steam is produced by a locomotive 

 boiler placed outside, together with the engine that drives 

 the suction pump. 



The pressure is generally maintained at two atmospheres; 

 it is rare that a heavier pressure is requited to maintain 

 the desired temperature. 



In order to maintain a suitable degree of humidity in 

 the rooms, a ring of 25 mm. pipes, perforated with holes 

 about 1 mm. in diameter, is placed on the floor ; the ring is 

 connected to the steam supply. This simple device enables 

 the degree of humidity to be regulated exactly, while it is 

 controlled by means of two electric thermometers acting as 

 hygrometers. The floor is slightly sloping, so that the water 

 of condensation can flow away. 



The tobacco is heaped upon the flooring, which is 

 raised to prevent it decaying and to allow the steam to 

 escape through the holes ia the ricg (described above), 

 placed just below the centre of the heap, A long iron pipe, 

 open above and perforated along its length, is introduced 

 vertically into the heap. The air passes along this tube into 

 the centre of the heap. The air is led from the vertical 

 tube to the perforated rings used to ventilate the outer part 

 of the heap. As the heap subsides here and there as it 

 ferments, the rings move in a vertical direction and should, 

 of course, be joined to the central tube in such a way that 

 they can move. 



Ordinary rubber tubes should be used to join the 

 central pipe and the rings, rather than the flexible metal 

 tube used in previous experiments. 



Imperial Preference and Tobacco. — There is a 



splendid opportunity, say.s the Rlioiesia Agiicultural Journal 

 for June 1919, for taking advantage of tie recent Imperial 

 Preferenceto establish Ithodesian tobacco on the British market, 

 for the preference given will amount to opproxiraately \s. id. 

 per B). on the present tariff. This gives Rhodesia considerable 

 advantage over American imports, and in view of the fact that 

 tobacco comparing very favourably with Virginia leaf can be 

 grown in Rhodesia, it is only reasosable to suppose that the 

 manufacturers in the United Kingdom will be very ready to 

 take all tte leaf of a suitable quality that Rhodesia can send. 

 It is not expected that there will be any leaf available for 

 export this year, bu' the preference mentioned will undoubt- 

 edly lead to considerably larger acreage being placed under 

 tobacco next s«aon, and c 'usequently a certain proportion of 

 the crop will be available for export. 



Eradication of Bermuda Grass.— Bermuda 



grass is the common lawn and pasture grass of the West 

 Indies, and is known botanically as Cynodon dactylo>i. It 

 is one of the most valuable grasses iu the tropics and sub- 

 tropics, but in the Southern States it is at the same time a 

 most pernicious weed. In the West Indies it also gives 

 trouble as a weed, but it may be said generally that its 

 valuable qualities are much greater than its bad. 

 Bermuda grass has two natural weaknesses : first, it is unable 

 to withstand shade, and secondly, the root stock is very 

 susceptible to winter killing. These two weaknesses are 

 utilir.ed for purposes of control in the Southern States. Sum-jier 

 shade crops, like velvet beans, are alternated with intertilled 

 crops, such as corn aod cotton; the soil being occupied with 

 oats or rye during the winter. Hogs are also useful in 

 eradicating Bermuda grass. They are fond of the root 

 stocks. 



