60 



was noticed in the patient during the period of observation, which 

 continued until August 28. 



/. O., age 18, Mexican.— He was taken to Vera Cruz August 13 

 and placed in the mosquito-proof ward. On August 28, at 9.30 a. m., 

 he was bitten by four mosquitoes, two of which had fed sixteen days 

 previously, at 4 p. m., on A. L., a fatal case of yellow, fever, forty 

 hours after the onset of the disease, and the other two had fed fif- 

 teen days previously, at 10.30 .a. m., on the same case fifty-eight hours 

 after the onset of the disease. The patient remained perfectly well 

 throughout the following month while under observation in the 

 screened room. 



M. R., age .?./, Mexican. — He was brought to Vera Cruz August 28 

 and kept in the screened ward. 'On September 1, at 6.30 p. m., he 

 was bitten by two mosquitoes which had fed nineteen days before, at 

 10.30 a. m., on A. L., a fatal case of yellow fever, fifty-eight hours 

 after the onset of the disease. The patient continued in his usual 

 health during Sepember 2 and 3. On September 4, at 2 p. m., on 

 going into the ward the patient was found wrapped in his blanket 

 and said he felt chilly and complained of slight temporal headache. 

 There was no elevation of temperature. 



The next case succeeded : 



Yellow Fever Produced by the Bites of Mosquitoes. 



Marcos Cruz (case XLII), age 21, born in Perote, a mountain 

 town free from yellow fever, where he has always lived. States that 

 he never had fever of any kind. He was physically sound on exami- 

 nation, and brought to Vera Cruz, where he was immediately placed 

 in a mosquito-proof room and kept under observation for fourteen 

 days, when he was bitten by 11 mosquitoes, as follows: 



On September 11, at 9 o'clock a. m., 3 mosquitoes which had fed 

 fifteen days previously, at 9.30 a.m., upon Trinidad Martinez, a fatal 

 case, fifty-one hours after the onset. At the same time, 3 other mos- 

 quitoes, which had fed fourteen days previously, at 2.30 p. m., upon 

 Hipolito Vasquez, a fatal case, sixty-nine hours after the onset of the 

 disease. At 2 p. m. of the same day he was bitten by 2 more mosqui- 

 toes, which had fed fourteen days previously, at 2.30 p. m., on Hipo- 

 lito Vasquez, sixty-nine hours after the onset. 



The next day, September 12, at 2.30 p. m., he was bitten by 3 

 mosquitoes, 2 of which had fed fifteen days previously, at 2.30 p. m., 

 on Hipolito Vasquez, sixty-nine hours after the onset of the disease, 

 and the other had fed sixteen days previously, at 9.30 a. m., on Trini- 

 dad Martinez, fifty-one hours after the onset of his disease. 



On September 12 and 13 the patient had no symptoms, and his 

 temperature remained normal. 



