YELLOW FEVER. 421 



preparation for the work in hand ; and to avoid 

 the announcement of pseudo-discoveries which, 

 when heralded by an enthusiastic but ignorant 

 explorer, are sure to pass current for a time, inas- 

 much as a majority of the profession find na time 

 for personal investigations, and do not realize the 

 ease with which an explorer in this field of inves- 

 tigation may fall into a serious error. 



Extracts from Report of Havana Commission. 



" In Havana, Dr. Sternberg gave a large share of his 

 time to the microscopic examination and photography 

 of the blood. No chemical examination was attempted. 

 The patients from whom specimens of blood were ob- 

 tained were mostly soldiers in the military hospital of 

 San Ambrosio. Ninety-eight specimens from forty-one 

 undoubted cases of yellow fever were carefully studied, 

 and one hundred and five photographic negatives were 

 made, which show satisfactorily everything demonstra- 

 ble by the microscope. These photographs were mostly 

 made with a magnifying power of 1,450 diameters, ob- 

 tained by the use of Zeiss's one-eighteenth-inch objec- 

 tive and Tolles's amplifier. Probably no better lens 

 than the Zeiss one-eighteenth (oil immersion) could 

 have been obtained for this work, and it is doubtful 

 whether any objective has ever been made capable of 

 showing more than is revealed ly this magnificent lens. 

 With the power used, organisms much smaller than 

 those described as existing in the blood of charbon or 

 of relapsing fever would be clearly defined. 



" If there is any organism in the blood of yellow fever 

 demonstrable by the highest powers of the microscope 

 as at present perfected, the photo-imicrographs taken in 



