YoL. V. No. 104. 



THE AGRICULTURAL NEWS. 



125 



TREATMENT OF ANTHRAX. 



Tlic following extract is taken from a paper on 

 the ' Preventive Inoculation and the Serum Methods 

 read before the National Veterinary Association, at 

 Buxton, in July 190-5, by Jlr. Stewart Stockman, 

 M.R.C.V.S., Chief Veterinary Officer to the Board 

 of Agriculture, London : — 



In ISSl, Pasteur JemonstrateJ that if the Bwi/las 

 anihracis be incubated at a comparatively high temperature, 

 42'5° C, it ceased to form spores, and underwent an attenua- 

 tion proportionate to the period of incubation at the 

 unsuitable temiierature. If subcultures were made from the 

 •original and incubated at 37' C, .spores were again formed, 

 Ijut the second culture maintained the same degree of 

 vii'ulence as the one from which it was made. In this way 

 <;ultures of graduated virulence can be obtained. Two 

 vaccines of different virulence are used. The first vaccine 

 •consists of a culture which has undergone the attenuation 

 process for twenty days ; the second, which is, of course, 

 stronger, has beeu attenuated for only twelve days. The 

 dose for the smaller animals (sheep and goats) is ], c.c, and 

 for the large j c.c. The vaccine is injected subcutaneously 

 behind the shoulder in the ox, and inside the thigh of the 

 .sheep. The interval allowed between the two operations is 

 fourteen days. Immunity is established in about a month. 

 It lasts for about a year on the average; that is to say, the 

 inoculations must be repeated every year. One must, of 

 course, take care when operating on a large herd or 

 flock, that only those animals which have received the 

 first vaccine get the second. 



It is advised in France to immunize the animals in the 

 spring so that tlicy will be resistant liefore the hot weather 

 comes on, when anthra.x is more prevalent. On examining the 

 returns for Great Britain of the past few years, I have failed to 

 find a material seasonal difference in the incidence of anthrax. 

 The effects of inoculation are .slight fever, with occasionally 

 an inconsiderable amount of tumefaction at the site of the 

 operation. Sometime.s, however, fatalities occur. When the 

 latter are reckoned on a large number of inoculated animals 

 the percentage is not high, 0"5 in sheep and 0"2o in oxen. 

 Unfortunately, however, the majority may occur on one farm 

 which causes one to hesitate before recommending a client 

 to employ the method. 



Statistics collected in France over a period of si.xteen 

 years show that inoculation by the Pasteur method was 

 practised on 4,497,011 animals, of which 1,870,806 were 

 reported upon. The mortality following upon the first 

 vaccination was 031 per cent., and 0'24 per cent, after the 

 second. The death rate for the rest of the year, that 

 is to say, after the immunity might be considered to be 

 established, was 0'36 per cent., where before employing the 

 method, it was reckoned at 10 per cent. If, then, one 

 •calculates the total result on these figures, the benefit derived 

 from the method is a reduction of the death rate from 

 10 per cent, to 0'91 per cent, from anthrax. 



Statistics collected from the Buda Pesth Laboratory and 

 the Pasteur Institute up to 1900 are given by Metchnikott' as 

 a total of 11,381,867, with practically the same results as 

 those mentioned above. 



Chauveau demonstrated that anthrax cultures could be 

 fl.ttenuated by cultivation under a high pressure of pure 

 oxygen or atmospheric air. 



Vaccines ju'epared in this way have been used in Chili 

 with alleged success, but they have ajiparently a tendency to 

 -acquire increased virulence if kept too long. Only one virus 



is inoculated at the dose of „L c.c. for sheep and j\ c.c. 

 for oxen. By such a method, one must expect to have 

 a larger number of failures, but I take it to be au expedient; 

 compromi.se to suit the conditions of a country where the 

 distances are great, the herds large, and the skilled operators 

 few. Inoculation against anthrax is only to be advised where 

 the annual losses from the disease render the method, with all 

 its disadvantages, a business proposition. It should not. of 

 course, be employed, for example, on pastures which are 

 believed to be free from anthrax. Since au animal may be 

 infected even fatally by the operation, it is advisable, where 

 circumstances permit, to confine the inoculated until the 

 innnunizing process is complete, in order to avoid the 

 possibility of a sick animal producing further contamination of 

 the pastures. 



The statistics above quoted are greatly to the credit 

 of the Pasteur method. Unfortunately, however, there 

 are others, which although on a much smaller scale, supply- 

 convincing proof that one cannot read into these figures, 

 collected mainly from clinical observation, their full 

 arithmetical significance. I refer particularly to the observa- 

 tions made in England in 1894, in which 6'6 per cent, 

 of 22.5 sheep died from inoculation after the second operation, 

 and an experimental test brought out the fact that immunity 

 could not be counted on for four months. 



(To he Continued.) 



RUBBER TREES AT GRENADA. 



The following particulars of India rubber trees 

 found on estates in the island of Grenada, are 

 contributed by the Agricultural Superintendent, in 

 a letter dated March 29, 1906:— 



In reply to your letter No. G. 352, I have the honour to 



inform you that I have now, to the best of my knowledge, 

 seen all the rubber trees planted in this island. 



The majority of them are Ca.stilloa trees, but there are 

 a few Heveas. Nearly all the trees arc }'0ung and grow very 

 slowly", and it will be some years before any are ready to be 

 tapped. 



The C'astilloa is, in most places, attacked by scale 

 insects and the attendant soot fungus (black blight). As the 

 trees get older, however, they throw off this to some extent, 

 and its effect seems chiefly to be a retarding of the growth 

 in the young stages. I am forwarding by this mail, 

 for the inspection of the entomologist, a specimen of the scale 

 which infests them. * 



The Hon. W. H. Lascelles, who is at present in the 

 island, has a number of trees which are doing well. 

 Mr. Gay, at the Gouyave estate, has a few trees with one 

 or two Heveas, and the Hon. G. S. Seton-Browne has 

 a dozen or so about eight years old. In both cases these 

 are growing together with cacao. Mr. W. G. Lang has 

 a number of quite young trees at Tuilleries, and proposes 

 this year to plant as much seed as he can obtain. 



With regard to seed, a few of the Castilloas in the 

 country districts will fruit this year, as will also a Hevea tree 

 with Mr. Gay ; but, in all cases, the owners require the seed 

 for their own planting. Two of the He\'eas at the Botanic 

 Station are now in flower, and the three Castilloas are also 

 flowering, so that a fair crop of seeds may be looked for. 

 This, however, will not be enough to supply local demands. 



* This insect has been identified as Dactijlopim citri. [Ed. ^.JV.J 



