March, 1909.] 



PESTS. 



TICKS ON DOGS. 



Valuable dogs are often killed owing 

 to the attacks of scrub (not cattle) ticks. 

 If the ticks are promptly removed a dog 

 will usually recover, but if they are not 

 detected the animal rarely survives. In 

 the case of woolly -haired dogs the insects 

 are difficult to find, in which case the 

 dog may be sheared and the ticks re- 

 moved. They should not be forcibly 

 pulled off, as the mandibles are in- 

 variably left in the animal's skin, and 

 the mischief goes on. Insects breathe 

 through their bodies, hence, if the pores 

 are closed by the application ot oil, 

 turpentine, or kerosene, the tick dies, 

 and may be extracted entirely. If the 

 ticks cannot be found, the following dres- 

 sing will be of some service :— Soft soap, 1 

 oz. ; Kerosene, one teacupf ul ; water, one 

 quart. Boil the soap and water together 

 until the soap is dissolved. When cool, 

 add the kerosene, and agitate the mix- 

 ture thoroughly for five minutes with 

 a rod. Wash the dog all over with some 

 of this mixture. Give internally 3 to 

 10 gr. of iodide of potassium in two table- 

 spoonfuls of water.— Queensland Agri- 

 cultural Journal. 



VIRUS FOR THE DESTRUCTION 

 OP RATS AND MICE. 



By H- E. Annbtt. 

 Professor of Comparative Pathology, 

 University of Liverpool. 



Kindly favour me with a small space 

 in your columns to explain the true 

 nature of the " Liverpool " virus for 

 mice and rats, which, according to the 

 editorial paragraph appearing in the 

 Journal of October 31, p. 1394, is supposed 

 to have been directly associated with an 

 outbreak of illness in a business establish- 

 ment in the city last July. 



The virus is manufactured, under my 

 superintendence, by the Incorporated 

 Liverpool Institute of Comparative 

 Pathology, founded for the furtherance 

 of the study of comparative patholoery 

 in all its branches, and especially for 

 research into the relation of the diseases 

 of animals to those of man, and devoting 

 any profits which may accrue from the 

 sale of its commercial products to 

 research in the subject of comparative 

 pathology, which up to the present, no 

 such profit accruing, has been assisted 

 largely by donors and subscribers. The 

 virus as issued by the Institute is 



certainly not a culture of the Bacillus 

 enteritidis (Gaertner), nor can tlie 

 " Danysz" bacillus in the form with 

 which I have carried on extensive in- 

 vestigations, and as issued by Danysz 

 Virus Company, Limited, London, be 

 identified with Gaertner's bacillus. 



The Danysz bacillus and the Liverpool 

 virus bacillus were obtained originally 

 from the intestinal contents of rats (the 

 " ratin" bacillus, issued as a rat virus by 

 the Ratin Company, London, was, I 

 believe, isolated from the urine of a child 

 by Neumann) ; and the virulence and 

 efficiency as vermin killers of these 

 original strains has been maintained for 

 a period of six months or seven years 

 bv suitable subcultures and passages 

 through various animals. 



These bacilli are members of a very 

 large group of allied organisms to which 

 the name " Salmonella" has been given. 

 In this group are included at present : 

 The bacillus of hog cholera (Salmon 

 a ud Smith) ; bacillus of swine fever 

 (MacFadyean) ; B. suipestifer (Schiitz) ; 

 bacillus of peste du pore (Lignieres) ; 

 B, paro&yphosus " B " oi several authors 

 (Brion and Kayser, Schottmuller, &c.) ; 

 B. icteroides (Sanarelli) ; B. enteritidis 

 (Gaertner) ; bacilli from various cases of 

 meat poisoning (Van Ermengen, Aertryk, 

 Trautmann, Giinther, &c.) ; bacillus of 

 psittacosis (Bohme) B. typhi murium 

 (Loeffler) ; bacillus of rat virus (Danysz 

 and others) ; bacilli of " Ratin" No. I. 

 (Neumann) ; bacillus of septicaemia of 

 calves (Thomassen) ; bacillus of diarrhoea 

 and dysentery of calves and other 

 domesticated animals (several authors). 



From a rough glance over this list, it 

 will be readily perceived that the 

 organisms are practically all of intestinal 

 origin, and have a very extensive dis- 

 tribution in Nature. Observations tend 

 to indicate that they are ordinarily 

 harmless inhabitants of the normal in- 

 testinal tracts of man and animals ; 

 but occasionally, under circumstances at 

 present but little understood, take on 

 pathogenic properties, the manifes- 

 tations of which exhibit a large degree of 

 specificity, for the species from which 

 the organisms were originally derived. 



The differentiation of members of this 

 list into two groups, of which the 

 B. enteritidis (Gaertner) forms the type 

 of one, and the bacillus of hog cholera, 

 or the B. typhi )tiuritim, may be taken 

 as the type of the other, is not a 

 very difficult task for any bacteriologist, 

 by appropriate cultural, biological, an d 



