60 CITY MILK SUPPLY 



by drinking goat's milk and less readily by inhaling infected dust and by 

 eating food that has been exposed to such dust. In this connection it 

 should be noted that while the micrococci succumb readily to heat 

 and disinfectants they manifest considerable resistance to drying. In 

 certain parts of Texas the indications are that dust transmission of the 

 disease is important. Possibly the disease may be spread by flies. 



Malta fever is characterized by profuse perspiration, constipation, 

 frequent relapses often accompanied by rheumatic or neuralgic pains 

 and sometimes by swellings of the joints. The disease is long drawn out 

 and has a mortality rate of about 3 per cent. In Texas it has been known 

 as Rio Grande or goat fever and is sometimes confused with typhoid 

 fever though practitioners often recognize that the disease is not true 

 typhoid. Isolation of the micrococcus and agglutination tests serve to 

 distinguish the diseases. In the United States, it is apparently in the 

 kidding season that the disease is most often contracted, for the reason 

 that it is at this time that the milk flow is heaviest and that at this time, 

 also, the rancher's whole family live with the goats. Precaution should 

 be taken to boil the milk and to locate the pens so that there is a mini- 

 mum of dust exposure to the family. 



Contagious Abortion. The bacillus of contagious abortion is common 

 in market milk and the fact that it was pathogenic for cattle roused the 

 suspicion that it might in some way be for man. Shroeder at one time 

 believed that Bad. abortus might be responsible for tonsillar troubles and 

 adenoids in children but neither he and Colton nor Mohler and Traum 

 were able to prove the theory by testing a large number of diseased tonsils 

 and many samples of adenoid tissue excised from children. 



Larson and Sedgwick in 1913 called attention to the fact that the 

 blood serum of children using milk from cattle infected with contagious 

 abortion, often contains antibodies against Bact. abortus. In a series 

 of 425 children whose blood was tested to either or both agglutination 

 and complement fixation 73, or 17 per cent, gave a positive reaction. Cer- 

 tain groups of these children gave a much higher percentage of positive 

 reactions; thus the children of one institution gave over 40 percent, and of 

 another as high as 48 per cent. Children that were fed on the milk of 

 herds known to be free from the disease did not give the reaction while 

 those fed on ordinary market milk did. The authors state that while it 

 could not be determined whether the presence of these antibodies in the 

 blood of children is the result of an infection or of antibody absorption 

 through the digestive tract they incline to the former interpretation be- 

 cause they consider it improbable that antibodies could be excreted in 

 quantities sufficient to give a positive complement fixation test. 



Cooledge found by experiment that Bact. abortus antibodies may be 

 present in milk in great concentration and that they may be made to 

 appear in the blood serum of adults by feeding them milk naturally 



