530 BACTERIA IX INFECTIOUS DISEASES NOT PROVED 



been perfected since Drs. Freire and Carmona made their researches, and 

 with which they were evidently not familiar. 



The failure thus far to find a specific microorganism in the blood or tis- 

 sues makes it desirable that a thorough research should be made with refe-' 

 rence to the microorganisms present in the alimentary canal, for it is possible 

 that in yellow fever, as in cholera, the disease is induced by a microorgan- 

 ism which multiplies in this situation. Additional researches are also re- 

 quired before we can say definitely that there is no germ demonstrable in 

 the blood and tissues. Having exhausted our resoui'ces by the method of 

 direct examination, and by cultures from blood drawn during life, it is 

 highly desirable that various culture media should be inoculated with mate- 

 rial taken, with proper precautions, from the various organs at the earliest 

 possible moment after death. 



The results of subsequent investigations made by the writer in Cuba 

 during the summers of 1888 and 1889 are given in the following summary 

 statement from the Transactions of the Tenth International Medical Con- 

 gress (Berlin, 1890) : 



Bacteriological Researches in Yellow Fever. 



The report relates to investigations made in Havana, Cuba, during the 

 summers of 1888 and 1889, in Decatur, Alabama, during the autumn of 1888, 

 and in the pathological and biological laboratories of the Johns Hopkins 

 University during the winters of 1888 and 1889. 



Forty -two autopsies were made in typical cases of yellow fever and seven- 

 teen autopsies in other diseases for comparative researches. 



Aerobic and anaerobic cultures were made from the blood, the liver, the 

 kidney, the urine, the stomach, and the intestine. 



The experimental data recorded in this report show that : 



The specific infectious agent in yellow fever has not been demonstrated. 



The most approved bacteriological methods fail to demonstrate the con- 

 stant presence of any particular microorganism in the blood and tissues of 

 yellow-fever cadavers. 



The microorganisms which are sometimes obtained in cultures from the 

 blood and tissues are present in comparatively small numbers ; and the one 

 most frequently found (Bacterium coli commune) is present in the intestine 

 of healthy individuals, and consequently its occasional presence cannot have 

 any etiological import. 



A few scattered bacilli are present in the liver, and probably in other or- 

 gans, at the moment of death. This is shown by preserving portions of 

 liver, obtained at a recent autopsy, in an antiseptic wrapping. 



At the end of twenty-four to forty-eight hours the interior of a piece of 

 liver so preserved contains a large number of bacilli of various species, the 

 most abundant being those heretofore mentioned as occasionally found in 

 fresh liver tissue, viz. , Bacterium coli commune and Bacillus cadaveris. 



Blood, urine, and crushed liver tissue obtained from a recent autopsy are 

 not pathogenic in moderate amounts for rabbits or guinea-pigs. 



Liver tissue preserved in an antiseptic wrapping at a temperature of 28 

 to 30 C., for forty -eight hours, is very pathogenic for guinea-pigs when in- 

 jected subcutaneously. 



This pathogenic power appears to be due to the microorganisms present 

 and to the toxic products developed as a result of their growth. It is not 

 peculiar to yellow fever, inasmuch as material preserved in the same way 

 at comparative autopsies, in which death resulted from accident or other 

 diseases, has given a similar result. 



Having failed to demonstrate the presence of a specific ' ' germ " in the 

 blood and tissues, it seems probable that it is to be found in the alimentary 

 canal, as is the case in cholera. But the extended researches made, and re- 

 corded in the present report, show that the contents of the intestines of yel- 



