Vol. XVI. No. 407. 



THE AGRICULTUKAL NEWS. 



379 



hogs which died from the disease, or were slaughtered 

 because of being infected, was 59,185. 



Even in the West Indies, where hogs are not as yet 

 kept in large herds, the disease has been in some instances 

 very destructive. The writer remembers that some years 

 ago there was an outbreak of hog cholera in Antigua, which 

 caused serious loss to the keepers of hogs in that i.sland 

 Hog cholera is a highly contagious disease of swine 

 caused by a living micro-organism or germ, so small that it 

 cannot be seen even under the highest power ot the micros 

 cope. But that it is a living agent is proved by the fact that 

 if liquid containing infective matter be passed through the 

 finest bacteriological filter, a very small amount of the filtrate 

 will produce the disease in a pig into which it has been 

 injected, and the infecting agent will increase in the pig's 

 system in a short time to such a degree as to be capable of 

 infecting more than a thousand other pigs So far as is 

 known the disease does not, however, affect othei- animals 

 or human beings. Although insanitary surroundings and 

 improper feeding tend to lower an animal's vitality, and so 

 perhaps render it more susceptible of disease, yet such condi- 

 tions cannot of themselves cause hog cholera. It can only be 

 produced by the specific micro-organism. 



There is another disease of hog.s, swine plague as it is called 

 in the United States, which is different from hog cholera, but 

 so closely associated with it that one disease seldom appears 

 without the other. Swine plague is an infectious pneumonia 

 which attacks swine when in poor condition, or when run 

 down by an attack of hog cholera. Professor Nelson S. Mays 

 in his book ' The Diseases of Animals', says it is probable 

 that germs of swine plague are widely distributed wherever 

 hogs are kept in large numbers, but the natural power of 

 resistance in the system of a health)' animal is sufficient to 

 prevent these germs from developing after entering the 

 system When, however, the system becomes weakened, the 

 germs develop, and death often results, not only directly 

 from the pneumonia, but from the hog cholera with which 

 swine plague is usually connected The difficulty of distin- 

 guishing these two diseases is so great that it is well to treat 

 suspected swine plague as if it were a case of hog cholera 



As was stated above, hog cholera, so far as is known, 

 can only be communicated by the introduction of the specific 

 germ of the disease. There is therefore no more certain way 

 of introducing hog cholera than by placing an infected hog 

 along with others. Infected hogs discharge the diseased 

 eerms from their bodies not only in their urine and fiwces, 

 but even in the secretions of the mouth, nose, and eyes. It 

 follows, therefore, that the bedding and litter, and even the 

 dirt itself in pens where an infected animal is kept must be 

 infected with the germs These germs may enter another 

 hog's system by means of fond and drink, and probably also 

 through wounds or skin abrasions. It is stated that the 

 gerni- possess great vitality, so that a locality where hog 

 cholera has broken out may remain infected for a long time. 



As to precautionary measures asiain'-t this disease, they 

 may be summed up in a few lines. Careful attention to see 

 that the hous are properly fed and supplied with pure water; 

 clean and sanitary quarters; aud lastly, all possible precautions 

 against the introduction of an infected animal among other 

 healthy ones. 



Up to the present time, the Farmers' Bulletin referred 

 to above states, no drug or combination of drugs is known 

 which can be regarded either as a preventive or a cure in the 

 true sense of the word for hog cholera, Only one agent 

 known can be regarded as a reliable preventive, that is 

 anti-hog cholera serum, prepared from the blood of an 

 immune hog which has been inoculated with the blood of 



a hog .suffering from the disease. The efficacy of this serum 

 as a protection was first brought to public notice by the 

 Bureau of Animal Industry in the United States in 1908. 

 Its value is now also generally recognized in England and in 

 many other countries While looked upon as most efficacious 

 when administered as a prophylactic, the serum has also an 

 undoubted curative value if administered in the early stages 

 of the disease. 



One great advantage of this treatment is th it, as the 

 serum does not contain any germs of hog cholera, it may be 

 safely employed to guard against the introduction of the 

 disease. The method of injection is a simple one, by 

 means of a hypodermic syringe. This treatment is to be recom- 

 mended in preference to any other for treating sick hogs. 

 Unfortunately it does not render healthy hogs permanently 

 immune. The period of immunity conferred by an injection 

 seems to last from about four weeks to two or three months, 

 varying according to the peculiarities of the individual hog, and 

 also to some extent according to the size of the dose, which is 

 graduated from a dose of 10 cubic centimetres for a small 

 pig weighing less than 10 tt)., up to one of 80 cubic centi- 

 metres for a hog weighing 175 fc. or more. Ordinarily, the 

 treatment of hogs already infected by hog cholera with 

 injections of serum alone is efficacious in the early stages of 

 the disease, but has only a slight effect when the disetse is 

 advanced. 



Complete immunity from the disease is obtained by the 

 injection of hog cholera virus in addition to the serum The 

 practice is to administer the germs of hog cholera in the 

 virus, and at the same time to give a dose of serum, which 

 will protect the hogs from cholera. The theory is similar to 

 that of vaccination. The virus entering the system of the 

 hog causes a r action, which results in an immunity like that 

 found in hogs which have recovered from a natural attack of 

 the disease; the serum given at the same time renders the 

 attack thus artificially produced a mild one, and so the hogs 

 thus treated are rendered iuimune for tlieir natural life. There 

 is, however, the danger in this treatment that, if the work is 

 not done properly, or a sufficient dose of serum of sufficient 

 strength not administered along with the virus, a serious case 

 of hog cholera may be produced by the latter. Although the 

 treatment with serum alone is simple enough for any intelli- 

 gent man who will follow the instructions supplied, to 

 undertake, yet it is agreed that the simultaneous inoculation 

 of virus and serum should only be practised by competent 

 veterinarians, who have had adequate training in such 

 questions. The conclusions to be remembered are put in 

 very few words by the Farmers' Bulletin already quoted: 

 if hog cholera appears among a herd, (1) isolate all sick 

 anima's; (2) use .serum, which is manufactured in several 

 State institutions, and by private firms licensed for the 

 purpose by the Secretary of Agriculture of the United States; 

 (3) employ stringent disinfecting measures; (4) submit to 

 a voluntary quarantine of your premises. 



Science Teaching in the Antigua Grammar 



School. — Apropos of the question of the stimulation of the 

 interest in education, especially scientific education in 

 secondary schools, which is the subject of the editorial in the 

 present issue of this Journal, an article by Mr. S. T. Christian, 

 B.A., an Assistant Master in the Antigua Grammar School, 

 in the issue for Trinity Term of the School's Revietv, gives an 

 interesting summary of what has been done for the teaching 

 of scientific subjects in the .school since its foundation in 1884. 

 The article in question is valuable as placing on record the 

 work done in this direction, and the assistance given to this 

 side of education by the Imperial Department of Agriculture, 

 as well as by the local Government. 



