58 
PATHOLOGY: LOVE AND DAVENPORT 
^Amer. J. Set., New Haven, 31, 1886, (377). 
2Proc. Amsterdam Acad., 17, 1914, (445); and 18, 1915, (1). 
3 This modification is essential, as the symmetrical apparatus of Michelson aud Morley 
does not admit of ray separation. 
A COMPARISON OF WHITE AND COLORED TROOPS IN RESPECT 
TO INCIDENCE OF DISEASE 
By Lieutenant-Colonel A. G. Love, M.C. U. S. A. and Major C. B. 
Davenport, Sanitary Corps, U. S. A. 
Read before the Academy, November 18, 1918 
This paper is an analysis of over half a million admissions to sick report of 
troops in camps in the United States. Of these 531,445 were for whites and 
15,186 for colored troops. The relative frequency of disease in the two 
'races' was as 974 to 1155; that is, the colored troops were about 19% more 
liable to go on sick report than the white troops. 
The grounds of sick report are very numerous; so we shall consider only 
the commoner ones. All comparisons will be of tlie so-called mean annual 
rate per 1000 men. The data are those collected for the Report of the Sur- 
geon General of the Army, 1918. Some comparative data have occasionally 
been included derived from the nine preceding annual reports. 
In many cases the morbidity rate is almost the same for the white and col- 
ored troops. In this paper particular attention is paid to those diseases that 
have a strikingly different rate in the two races. It is to be kept in mind 
that all troops had been subjected to the same examination at induction, in 
order to exclude chronic diseases; and that they lived under equally good 
sanitary conditions. 
First, may be considered the diseases that are commoner in colored than 
in white troops. These fall into four groups (a), those in which the excess 
is due to the fact that fewer of the colored men had become artificially im- 
munized by inoculation before, or at, mobilization. They probably brought 
their disease to camp; or failed to get a reaction there; (b) those in which 
there is a lower natural immunity in the negro; (c) venereal disease and its 
complications, (d) other diseases. 
(a) Of the diseases that are due to lack of acquired immunity, smallpox is 
the most striking. The morbidity rate for this disease is for colored troops 
9 times that for white troops (there being 146 admissions altogether). Chick- 
enpox was relatively 8 times as common in colored as in white troops. 
(b) Of the diseases for which negroes lack relative natural resistance tuber- 
culosis of the lungs and pneumonia take first places. There were over 2J 
times the admission rate for tuberculosis of the lungs in colored as in white 
troops in 1917. This is a little greater difference than the average of the past 
0 
