48 
Nearly every case of the disease found during the entire trip was 
either living at the time in a sand}- district or had lived in such a place 
a few years previously. As soon as I entered the sandy areas, uncina- 
riasis was found. As soon as I left the sand, as at Albany, local foci 
of infection of uncinariasis disappeared. 
Inquiry among physicians at first failed to elicit any definite state- 
ment regarding the soil on which anemia was most frequent, but upon 
going farther south several ph 3 ^sicians were met whose experience 
fully confirmed ni}^ observations on this point. One physician in par- 
ticular, Dr. A. M. Burt, of Macon, was of the emphatic opinion that 
in bringing the condition which 1 have interpreted as uncinariasis into 
connection with the sand}" soil, I bad found the keynote to the distri- 
bution of the entire disease. Dr. McHatton, of Macon, called my 
attention to the fact that in antebellum da}"s the slave owners in the 
Lower Mississippi Yalle}" frequently provided special quarters, which 
were removed from the sand districts, and to which they sent the 
dirt-eating and other sick negroes and also negresses about to be con- 
fined, the view being held that a clay soil was more salubrious than a 
sandy soil. This view, in fact, I found to be rather prevalent among 
the farm hands. Time after time they remarked, ' AVe were never sick 
so long as we lived in a clay district,” “This disease developed after 
we moved upon sand,” etc. 
This view that uncinariasis follows the sand is supported b}- evi- 
dence obtained in Alaska I)}" Mr. F. A. Lucas. After the discovery 
was made that uncinariasis, caused b}" Uncinaria Liicasi, was preva- i 
lent among the seal pups, Lucas (see above, p. 39) showed that it was 
practicall}" onh" the seals on the sandy rookeries which were infested ' 
with the parasites. | 
As stated above (p. 39), I have also observed two outbreaks of j 
uncinariasis among sheep and goats, caused b}- Uncinaina trigonocephaJa ' 
(Rudolphi, 1809) Ralliet, 1900, on more or less sandy soil, and have j 
further confirmatoiy facts in connection with one outbreak of the 
disease among dogs. Since returning from my trip I have found ' 
at least one reference in literature on uncinariasis and ground itch to i 
the efi'ect that the soil in districts where certain cases have occurred 
was more or less sandv (see p. 62), but I have not }"et found that any \ 
author lays stress upon this point. Lj 
In view of all the data at hand, I have no hesitation in expressing ' 
the opinion that uncinariasis, caused hy Uncinaria arnericana^ is pre- i 
eminently a disease of sandy localities and that cases found in clav or : 
rocky areas can usualh" be traced to a former visit or residence in a 
sand}^ place. 
Just wh}" this disease should follow the sand rather than the cla}" is ! 
not absolutel}" clear. Three explanations have occurred to me as 
working ly-potheses which, though not absolutely satisfactoiy as final, - 
will, I believe, explain part of the mvstery. 
