284 REPORT OF THE HARVARD AFRICAN EXPEDITION 
were aneurysms of the aorta, in one, a gumma of the brain, and in the other a 
spontaneous cerebral haemorrhage. He has described as a tertiary lesion of 
yaws, degeneration of the intima of the aorta with yellowish patches of athero- 
matous change, the lesions being as a rule about 2 mm. above the aortic cusps 
but not appearing to invade the valve itself. The atheromatous change may 
extend down to the iliac bifurcation. Aneurysms are stated to be extremely 
common in late yaws, all varieties being encountered. He reports that the 
heart muscle in old yaws cases seems to be definitely affected. The epicardium 
is more or less opalescent with porcelain-like patches. These areas are also 
frequently seen in the endocardium. In the liver Choisser frequently found 
small superficial punctate scars which showed on section areas of degeneration 
with associated round cell infiltration. Actual cirrhosis was rare. Gummata 
of the liver were also rare but did occur. Haemorrhages into the brain and 
cord were common, especially in young adults. Stitt and also Choisser illus- 
trate the aortas from two cases of tertiary yaws showing marked aortitis, and 
two aortic aneurysms, thoracic, and abdominal, from cases of tertiary yaws. 
Stannus alludes to the fact that a syphilitic may be infected with yaws 
and vice versa, and says that this is held sufficient by the majority to substan- 
tiate the two disease entities. The experiments of Powell! who reported six 
successful inoculations of syphilis in yaws in man and three of yaws in syphilis 
in man, support this view. But with reference to this point some of the evi- 
dence while not conclusive certainly tends to associate the two conditions very 
closely. 
Jahnel and Lange,” using three strains of Spirochaeta pertenuis from different 
sources failed to infect by inoculation a number of patients with general paraly- 
sis of the insane, but in the following year * they succeeded with another strain 
of this organism in successfully inoculating a typical case of general paralysis, 
there having resulted a granuloma with scaly crust which contained spiro- 
chaetes. In a later publication,’ they state regarding their further inoculative 
experiments of this nature, that they cannot be taken to support the idea of 
the unity of the treponemal virus but perhaps are only manifestations of a 
group reaction. They think, from their own observations and those carried out 
by other investigators, that the facts can best be explained by postulating a 
group of viruses of yaws and syphilis with characteristic yaws virus at one pole 
and characteristic syphilis at the other, tropical or indigenous native syphilis and 
some variety of framboesia being some of the intermediate forms. The human 
experiments by Sellards and Lacy ° also demonstate the difficulties that might 
ensue in attempting to differentiate yaws and syphilis by inoculation experiments, 
particularly on account of the time when immunity following inoculation is es- 
tablished, and the time which it persists. 
Differences observed in the immunity reactions in the laboratory between 
1 Powell: Proc. Royal Soc. Med., Section Trop. Dis. and Parasit. (1923), XVI, 15. 
? Jahnel and Lange: Klin. Woch. (1926), V, 2118. 
3 Ibid., Muench. Med. Woch. (1927), LX XIV, 1487. 
4 Iiid., Klin. Woch. (1928), VII, 2138. 
5 Sellards and Lacy: Loc cit. 
