304 REPORT OF THE HARVARD AFRICAN EXPEDITION 
tics, certain special characteristics sometimes serve to distinguish them, even 
though they have only a very relative diagnostic value. He emphasizes that 
this is true because these distinctive characteristics are not present in a unl- 
form and regular way in all stages of the pathological processes. In the struc- 
ture of the granulation tissue of the nodular tumors, the lymphocytes and 
plasma cells are the paramount feature. However, in the beginning he remarks 
one will often be able to distinguish the nodular syphilitic lesion owing to the 
fact that it is sharply delimited and very compact through an infiltration of 
round cells, these cells separating the area from the surrounding, less compact, 
newly-formed connective tissue. In the case of framboesia the cellular in- 
filtration has a very much less indistinct margin or zone of connective tissue, 
and the zone of connective tissue also shows an infiltration with leucocytes, 
and there is an inflammatory zone. Hallenberger believes that the same dis- 
tinction applies to gummatous formations, the growth of newly-formed con- 
nective tissue in both syphilis and yaws being surrounded by a compact wall 
of lymphocytes. However, only in the case of syphilis is the sharp boundary 
preserved for a long time. In case of gumma in framboesia, a diffuse area of 
infiltration is very soon formed. 
He also believes that an additional point in diagnosis is given by the de- 
generation of either the chronic inflammatory granulation tissue or, in other 
cases, of the newly-formed connective tissue, which degeneration begins in the 
center of the infiltration. In the case of syphilis this degeneration takes place 
from caseation or through mucous or fatty degeneration; in the case of gumma 
in framboesia, it occurs through gelatinous degeneration or by means of a 
purulent softening (eitrige EKinschmelzung). The latter is more common and 
is also observed in framboesial nodules in which, though more rarely, necro- 
sis may occur. Hallenberger believes that this purulent degeneration is not 
attributable to syphilis and that if such degeneration occurs it is an indica- 
tion that the condition is not syphilitic. 
He points out that these characteristics of the two diseases, which are more 
or less specific, disappear as soon as the formation of the ulcerative lesions is 
complete, when secondary infections may occur which likewise alter the pic- 
ture. In such instances, the syphilitic infiltration is modified as a result of the 
extensive invasion with leucocytes and the otherwise sharp border of the syphi- 
litic infiltration observed in the earlier stages of the infection, becomes indis- 
tinct. ‘This is especially true in the cortum which the earlier lesions of syphilis 
have not usually appreciably modified. He states that for these reasons in 
many of the late lesions, the two disease processes can no longer be distin- 
guished from one another by the histological examination or, indeed, from 
other chronic ulcerations of the skin. In the ulcerative lesions, he points out 
that the marked proliferation of the epithelium along the margins of the ulcers 
is no special feature of framboesia. He believes, however, that a characteris- 
tic that is almost always present in the late lesions of framboesia is the behavior 
of the plasma cells, though he states that this also cannot be given absolute 
value for diagnosis. He remarks that just as the quantitative amount of plasma 
