438 BACTERIA IN INFECTIOUS DISEASES. 



and a suitable culture-medium for a variety of bac- 

 terial organisms and microscopic fungi. At the 

 extremity of the urethral canal, bacteria are always 

 found in considerable numbers, and the urine of 

 healthy persons, or of yellow fever patients, is 

 necessarily contaminated with these when it is 

 voided. Urine " allowed to evaporate spontane- 

 ously" is presumably exposed to the air and to 

 inoculation with the numerous germs which it 

 contains. 



Dr. Carmona says : " The black vomit sediment 

 appeared to be formed for the greater part of 

 blackened mycelial threads, and other bodies of 

 different forms and sizes, also black." 



The uniform testimony of competent micro- 

 scopists who have heretofore examined black 

 vomit is, that the dark color is due to the presence 

 of blood, altered by the acid secretions of the 

 stomach, which escapes from the hypenmnic mu- 

 cous membrane during the later stages of the 

 disease, when passive hemorrhages are common. 

 The writer has repeatedly verified this fact, and, 

 while in Havana, made photo-micrographs, which 

 show that the little dark-colored flocculi in the 

 vomited material are made up of decolorized blood- 

 corpuscles and of amorphous masses of dark ma- 

 terial which is presumably haemoglobin from these 

 decolorized corpuscles, changed by the acid secre- 

 tions of the stomach. A microscopic examination 

 of black vomit or of the transparent ncid fluid 

 ejected at frequent intervals before hemorrhages 



