492 
THOMPSON YATES LABORATORIES REPORT 
in a barrack in which there had been several hundred deaths through yellow fever 
during the previous year of Spanish occupation ; none of these prisoners acquired 
the disease, but some twenty-five of their custodians fell ill or died of the fever. 
Through the courtesy of Major Gorgas we were enabled to see the distribution 
of the fatal cases of yellow fever in the city for the past ten years. In these it was 
rather striking that the more disreputable quarters of the town were free from deaths 
from this cause. Immigrant women are few, and presumably the inhabitants are all 
' immunes ; ' still it is not improbable that the infective agent is harboured amongst 
them. 
These few notes on some epidemiological points are submitted in the hope that 
they may be of some interest to students of the perplexing questions and of the 
unravelled natural history of yellow fever. 
B. Abstract of Interim Report 1 
i. Sufficient search reveals the presence of a fine, small bacillus in the organs of 
all fatal cases of yellow fever. We have found it in each of the fourteen cadavers 
examined for the purpose. In diameter the bacillus somewhat recalls that of the 
Influenza bacillus ; as seen in the tissues it is about 4 /x in length. 
1. This bacillus has been found in kidney, in spleen, in mesenteric, portal, and 
axillary 2 lymphatic glands, etc., taken from yellow fever cadavers directly after death. 
In the contents of the lower intestine apparently the same bacillus is found, often in 
extraordinary preponderance over other micro-organisms. Preparations of the pieces 
of ' mucus,' which are usually if not always present in yellow fever stools, at times 
may almost present the appearance of ' pure culture.' 
3. Preparations of the organs usually fail to show the presence of any other 
bacteria, whose absence is confirmed by the usual sterility of cultivation experiments. 
4. It is probable that this same bacillus has been met with, but not recognized, 
by three other observers. Dr. Sternberg 5 has mentioned it ; and he has also re- 
corded the finding of similar organisms in material derived from Drs. Domingos 
Freire and Carmona y Valle, but he did not recognize its presence frequently, 
probably on account of the employment of insufficiently stringent staining technique. 
5. It is probable that recognition has not been previously accorded to this 
bacillus by reason of the difficulty with which it takes up stains (especially methylene 
blue), and by reason of the difficulty of establishing growths on artificial media. 
1. The completion of the interim report of which this is an abstract was interrupted by the onset of attacks of yellow 
fever in both of us. The loss of my much lamented colleague renders it advisable to submit this shortened report only for the 
time being. — H.E.D. 
2. We find these constantly enlarged and much injected, though whether this is specific we are not able to say 
3. Report on Etiology and Prevention of Yellow Fever, 1890. 
