YELLOW FEVER EXPEDITION 
5i9 
The conclusion which we thought probable was that they were the local lesion 
caused by the introduction and local development of the parasite of yellow fever, and 
that the condition found in the lymphatic glands was of the same nature. The mode 
of proof by watching the progress of the bite of an infected gnat upon an experi- 
mental case could not be made, and unfortunately the Commission under Major 
Reed do not refer to the matter. 1 Another mode of proof was by determining the 
presence of the yellow fever parasite in the locality. After scrubbing the skin with 
lysol and then with spirit, the spots were stabbed with a lancet, and the blood, which 
freely exudes, was taken directly into a tine sterile capillary without touching the 
skin. Examination of specimens thus taken were examined in the fresh state, and 
also stained with carbol fuchsin. In the stained condition a few small, fine bacilli 
from 2 to 6 /x in length were found in scanty numbers, sometimes in tiny groups of 
four or five, sometimes singly ; besides these bacillary forms sometimes small coccoid 
bodies in pairs or singly could be found. It was suggestive that these might be the 
spherical shape assumed by the bacilli in consequence of the bactericidal action of the 
blood, especially from the specimen of a late case (P.-M. 11), who had many typical 
bites when admitted on the fifteenth day ; in these some little groups contained, 
apparently, stages between the complete bacilli and the coccoid forms. Here there 
is, of course, a risk of contamination with skin microbes. At a later date after my 
illness I examined some bites (which were rather swollen and due to the entrance of 
several C. fatigans during one night through neglect of closing the mosquito net) ; 
the blood obtained contained many ' polynuclear' leucocytes, in some of which 
ingested bacilli, similar to our small bacillus, were found, as also in the salivary sacs 
of the gnats themselves ; this was very suggestive of an introduction of bacilli by the 
gnats (Plate VIII, Fig. 2). 
B. Lymphatic Glands 
Since it appeared likely that the infection of yellow fever was introduced by 
some such agency as the gnat, it was possible that, the infection being local and 
superficial, there might be some signs of lesion about the corresponding super- 
ficial lymphatic glands. Our attention was more particularly attracted to this point 
by the marked enlargement, deep congestion, and juiciness of the axillary glands in 
our fourth autopsy, on October 29, 1900. After this, the investigation of the axilla 
became a constant feature of the clinical examination of patients ; in some cases the 
inguinal and femoral regions were also felt, but comparatively little attention was paid 
to these owing to the obvious source of fallacy during life. 
In forty-four cases of undoubted yellow fever, palpable and marked enlargement 
of the axillary glands is noted thirty-nine times, questionable enlargement three times, 
1. It is obvious that if a single bite has caused the disease, the lesion, even if 'typical,' might be overlooked. I must frankly 
own that I should have anticipated finding the small bacillus in greater numbers in the axillary glands. 
