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overlooked. The malarial germ has to pass through the body of cer- 

 tain mosquitoes before attaining its highest development or its full 

 life history. So far as we know as yet, certain mosquitoes are neces- 

 sary secondary hosts in the development of this disease germ. The 

 malarial germ is an animal organism. It belongs to the group of 

 animals known as Protozoa, and from analogy it is altogether likely 

 that the as yet undiscovered germ of yellow fever will also prove to 

 belong to the same class of parasitic organisms. The parasite which 

 causes Texas fever in cattle is also analogous to the minute spore 

 which causes malaria in human beings. It inhabits the blood just as 

 does the malarial parasite, and is conveyed by a biting insect; in this 

 case the cattle tick, just as the former is conveyed by certain mosqui- 

 toes. With diseases caused by bacterial organisms (which belong to 

 the plant kingdom and not to the animal kingdom), a biting insect is 

 not necessary for their transfer from a sick individual to a healthy 

 one in the majority of cases. Such diseases are notably typhoid fever, 

 cholera, and pulmonary consumption. With these diseases, and more 

 especially the first two, the agency of non-biting flies as transmitters 

 becomes important, and for this country their agency in the transfer 

 of typhoid fever is especially important. It has been known for some 

 time that flies may carry bacilli and bacteria on their feet. That was 

 experimentally proven by allowing flies to walk over cultures, and 

 after allowing them to walk upon sterilized media the same bacteria 

 developed. Moreover, as early as 1888 it was shown by an Italian 

 investigator that flies fed upon pure cultures of typhoid bacillus were 

 able to transmit virulent bacilli with their excrement. Further early 

 observations showed that flies are important agents in the transmission 

 of Asiatic cholera. 



Typhoid fever was astonishingly prevalent in the concentration 

 camps in this country at the outbreak of the war with Spain, and the 

 disease received a thorough investigation at the hands of a special 

 commission of army surgeons appointed for the purpose. It was 

 shown that although excellent preventive measures had been recom- 

 mended in circulars issued by the Surgeon-General of the Army, these 

 instructions were not carried out in many carhps and that the excre- 

 ment of the troops had not been properly cared for. Flies were found 

 to swarm over the infected fecal matter in the pits and then proceed 

 to the mess tents and feed upon the food prepared for the soldiers. 

 This was convincingly shown by the fact that where lime had been 

 sprinkled over the pits flies with their legs whitened by the lime were 

 found upon the mess tables. In the report published by one of the 

 members of the commission a number of significant and interesting- 

 facts relating to typhoid fever were brought out. It was shown, for 

 example, that the virulent germs may be excreted by a person for 

 some time before he is known to have typhoid. It was also shown 

 that such germs may be found in the excrement for a long time after 



