SEPTEMBER 13, 1918] 
was made by scratching the skin and rubbing 
in, eleven crushed lice in one case, and excreta 
voided by the lice in the other. Both men de- 
veloped typical symptoms of the disease, with 
a relapse in six to eight days. The inoculation 
of louse excreta into scratches has been re- 
peated a number of times, and in every case an 
attack of the disease has resulted. 
It was found that the incubation in man, 
when infected by scarification, was remarkably 
constant, 7. e., six to eight days, and the ease 
and certainty with which infection could be 
produced pointed to the inoculation of the con- 
tents of crushed lice or louse excreta as in all 
probability the common, if not the invariable, 
method of transmission. 
. The excreta obtained by shaking through the 
gauze cover of the boxes in which the lice were 
confined were used in the form of a dry pow- 
der, which remained infective for at least six- 
teen days. In parallel experiments with the 
excreta of normal lice which had not been fed 
on trench-fever patients no symptoms of the 
disease were produced. 
, That a very small amount of blood, such as 
might be contained in ten lice, does not di- 
rectly convey the disease through an excoria- 
tion of the skin, is indicated by the negative 
result obtained by rubbing 5 c.mm. of infective 
blood into scratches on the skin of a volunteer. 
Moreover, the following series of experi- 
ments points to the fact that the louse, after a 
meal of infected blood, does not void infective 
excreta for some days. Lice were fed on a 
trench-fever patient on one day only, and then 
on healthy men. Excreta collected on the first, 
third, fifth and eighth days after infection 
gave negative results, while those collected on 
the twelfth and twenty-third days proved viru- 
lent. The virus, therefore, would appear to 
undergo some preparation in the insect before 
it becomes infective. Whether this change in 
the louse is due to a simple multiplication on 
the part of the hypothetical microorganism, 
or to a cycle in its development, is as yet un- 
determined. Further, it was shown that the 
ingestion of louse excreta did not produce 
trench fever in two men who daily swallowed a 
dose for seven and fourteen days, respectively. 
SCIENCE 
263 
GRANITE FOR BUILDING IN- 1917 
THE total value of granite sold for building 
stone in 1917 was $2,881,128, a decrease of 
$1,083,305, or 27 per cent., compared with 
1916. The rough stone sold was valued at 
$590,310, which was $312,736, or 35 per cent. 
less than in 1916; the dressed or manufac- 
tured stone was valued at $2,290,818, which 
was $770,569, or 25 per cent., less than in 
1916. Accurate figures showing quantities 
are not yet available, but owing to a general in- 
crease in price the decrease in percentage of 
output was considerably more than in value. 
The statistics given were compiled under 
direction of G. F. Loughlin, of the United 
States Geological! Survey, in cooperation with 
the National Building Granite Quarries’ 
Association and the State Geological Surveys 
of Georgia, Maryland, Minnesota, Missouri, 
New Jersey, New York, North Carolina, Penn- 
sylvania, Virginia, Washington and Wiscon- 
sin. ‘ 
Sales of granite for building were reported 
from 26 states in 1917 compared with 28 in 
in 1916. Massachusetts, with a total value of 
$646,506, and Maine, with $525,604, ranked 
first and second. New Hampshire, second in 
rank in 1916, was third in 1917, with a value 
of $337,233. Massachusetts, with $132,700, 
and Maine, with $109,941, were the only 
states whose sales of rough granite exceeded 
$100,000 in 1917, and each of these showed a 
decrease of about one third compared with 
1916. New Hampshire followed with $78,484, 
a gain of about one quarter. Pennsylvania, 
which ranked first in sales of rough granite in 
1916, with a value of $224,360, was credited 
with only $87,978 in 1917. The few other 
states that showed gains had values of less 
than $15,000. 
In sales of dressed granite also Massachu- 
setts, with $513,806, and Maine, with $424,663, 
were the leading states. Maine, however, has 
made continuous gains in 1916 (2 per cent.) 
and 1917 (55 per cent.), whereas Massachu- 
setts in the same years has suffered losses of 
17 per cent. and 19 per cent., respectively. 
North Carolina’s output, chiefly stone for 
mausoleum work, though classed previously as 
