260 INFECTIVE DISEASES. 



The virus may be conveyed by infected ships, and has in this 

 way made its appearance at British and French seaport towns. 

 The disease is generally believed to be contagious, but the source 

 ■of the virus is not known. According to Sternberg the virus is not 

 conveyed by water, but spreads where there is overcrowding and 

 filth. 



Bacteria in Yellow Fever. — Freire asserts that there is a 

 specific micrococcus in yellow fever which can be grown on all 

 ordinary nutrient media, and that cultures can be used for protective 

 inoculation with satisfactory results. Carmonay Valle also claims to 

 have discovered the contagium ; but Sternberg, who has carried on 

 investigations extending over several years, maintains that there is no 

 characteristic micro-organism present in the blood or in the tissues 

 after death. Aerobic and anaerobic cultures were made from the 

 blood, Kver, kidney, urine, stomach, and intestines. The liver was 

 found to contain after death a number of bacilli, most frequently 

 Bacillus coh communis and Bacillus cadaveris. Blood or fresh 

 liver does not produce any disease in rabbits or guinea-pigs, but 

 liver tissue kept for forty-eight hours and inoculated subcutaneously 

 in guinea-pigs is extremely pathogenic. Similar results occur after 

 inoculation of healthy liver which has been kept in the same way. 

 We may conclude from these experiments that the nature of the 

 ■contagium is unknown. 



Stamping-out System. — Sternberg states that there are many 

 facts relating to the origin and extension of yellow fever epidemics 

 which support the theory that the virus is present in the evacua- 

 tions, and that accumulations of fsecal matter and of organic 

 material of animal origin furnish in certain climates a suitable soil 

 for the development of the contagium. According to this view the 

 ■evacuations should be thoroughly disinfected, and with other sanitary 

 precautions and efiicient quarantine at seaports, the disease may 

 be stamped out, and the danger of importation from tlie natural 

 iome of the disease reduced to a minimum. 



