Vol. XI. No. 258. 



THE AGRICULTURAL NEWS. 



95 



injury, such as a bullet piercing the tender heart tissues, 

 would produce a rot of the crown. It is safe to say that most 

 of the reasons given as to the causes were based on inaccurate 

 or incomplete observations, together with a lack of any 

 experiments to substantiate them. The rapid spread of the 

 disease in itself seems good evidence of its infectious nature, 

 for it does not stop in one valley or one grove, but fre- 

 quently spreads over a hillside and into the next valley, 

 always beginning in a small way and from that spreading 

 sporadically over the entire grove. If the disease were due 

 to soil or to climatic changes, many or all of the trees would 

 show signs of the rot about the same time. It could hardly 

 be supposed that this might be accounted for by variation in 

 individual resistance, since in the end most or all of the trees 

 contract the disease.' 



Johnston isolated strains of bacteria from diseased trees 

 in Cuba which, when inoculated into healthy trees, produced 

 the disease. The same bacteria were recovered from the 

 inoculated trees, re-inoculated again, and again recovered; this 

 proves as conclusively as possible that the organisms were 

 the cause of the disease, which must therefore be regarded 

 as infectious. The inoculations were made by boring a hole 

 into the heart tissues and then injecting the fluid containing 

 the bacteria. At the same time, control experiments were 

 made by boring the hole without injecting the bacteria. In 

 no case did the controls show any sign of a soft rot, so that 

 they indicated clearly that mere mechanical injury of the heart 

 tissues will not cause the disease. 



By means of a long series of comparative culture experi- 

 ments, Johnston showed that the bacteria from cocoa nut 

 trees infected with bud rot were indistinguishable from 

 Badlhis coli — an organism found in the human colon. More- 

 over, pure cultures of B coli caused a rot of cocoa nuts prac- 

 tically identical with bud rot. Thus the cocoa-nut organ- 

 isms must be regarded as strains of B. coli'. This is a most 

 important conclusion, as it is the first instance in which 

 a bacterium infesting animals has been found to produce 

 a plant disease. Some further results of Johnston's work 

 will be referred to in the next number of the AgrlndUiral 

 News. 



BACTERIOLOGICAL WORK IN JAMAICA. 



A supplement to the Jamaica Gumtte dated Thursday, 

 November 16, 1911, contains the report of Dr. H. H. Scott, 

 M.D., M.R.CS., L.R.C.P., Government bacteriologist, on the 

 work done by that officer between his arrival in Jamaica, on 

 January 6, and the end of the official year, March 31, 1911. 

 The work has been arranged so that part of the day is 

 employed at the Hope Laboratory in carrying out investiga- 

 tions connected with the Agricultural 1 lepartment, and part 

 is devoted to consultations and pathological work at the 

 Hospital. In the report, the work is described under the 

 following heads : (1) bacteriological examination of samples 

 of water-supplies; (2) veterinary pathology in connexion with 

 the Government Farm; (3) maintenance of the culture of rat 

 virus; (4) work in conneson with fermentati'on. 



As regards the first of these, bacteriological examina- 

 tions of the main supplies of water to Kingston are carried 

 out every month, for the Kingston General Commissioners. 

 The scheme according to which the samples of water are 

 taken for examination is described, and it appears that, 

 during the time under report, twenty-.six such samples have 

 been examined for their bacterial characteristics. 



In the work connected with veterinary pathology, by far 

 the largest number of specimens examined consisted of blood 

 smears from cattle suspected of suffering from Texas lever, 

 at the Government Farm; evidence was found in several 

 cases of the presence of the typical Pirosoma [Piroplasma] 

 hu/eminum, conveyed by the bite of ticks. A matter of 

 some general interest is that material from a horss with symp- 

 toms of lymphangitis, .strongly simulating farcy, gave good 

 specimens of Sairfuiromyrts farciminosus, which is the or- 

 ganism of epizootic lymphangitis (see West Indian Bulletin, 

 Vol. XI, p. 31). 



It is stated that the results with rat virus have not, so 

 far, been very encouraging, and reference is made in this 

 connexion to work in Madras, Calcutta and Burma which has 

 not succeeded in showing that the disease produced by the 

 virus is transmissible from rat to rat. There had been no 

 demand, recently, for the virus, in Jamaica; but the cultures 

 were being maintained at the proper strength, in case such 

 a demand may arise. 



The work in connexion with fermentation is largely con- 

 cerned with the provision of pure yeast cultures for rum 

 manufacture. The preparation of these takes about three 

 weeks for completion, and during the whole of this time 

 there must exist the greatest care in order that contamination 

 may be prevented. A matter that evidences the importance 

 of care in the work is that a small amount of contamination 

 at any stage of the preparation of a culture would quickly 

 cause disastrous results, on its introduction into a distillery. 

 This work is not merely routine in nature, as it includes 

 a large amount of technical labour which exhausts time, but 

 does not exhibit its existence in a large way when results 

 are presented. 



A detailed report of the work for the Medical Depart- 

 ment shows that part of this is done on behalf of the Typhoid 

 Investigation Committee, appointed to inquire into the preva- 

 lence of typhoid fever in Kingston and its suburbs. A dis- 

 ease known in the island as vomiting sickness is receiving 

 special attention by Captain Potter, R.A.M.C., and permis- 

 sion has been obtained from this investigator to announce 

 that work in collaboration, by the writer of the report, has 

 succeeded in sho^viDg the existence, in cases of this disease, 

 of an elongated, protozoallooking body, in many of the red 

 corpuscles which did not stain as a rule, but, in some few 

 instances, gave a spot of stained substance at one end. The 

 possibility is expressed that bodies of the kind constitute one 

 stage of the disease, only met with at some definite period of 

 the illness. 



Considerable attention is given in this part of the report 

 to vaccines and their employment in disease. With relation 

 to this matter, much ignorance still appears to exist in regard 

 to the mode of use of these bodies, and to the way in 

 which they produce a curative condition'. The fact should be 

 properly realized that vaccines do not cure, of themselves: but 

 that their administration causes a reaction to take place in 

 the tissues, which brings about the removal of the disturbing 

 influence. The conclusion from this fact may be quoted from 

 the report as follows : ' When this idea is grasped, vaccine 

 therapy will no longer be regarded as a " dernier ressort" to 

 which appeal is made after everything else has been tried. 

 Such a procedure is unfair from the points of view of both 

 the patient and the bacteriologist. For when vaccines are 

 tried at a late stage, after all recuperative power is lost or 

 when it is at such a low ebb that no reaction is possible, not 

 only has the time gone by when any treatment is availing, but 

 the vaccine therapy in consequence falls into di.srepute.' 



