610 
NATURE 
| APRIL 25, 1907 
The whole account will well repay a careful perusal, 
and anyone engaged on the design of a flying 
machine will find much useful information in the 
results of the varicus experiments on bodies rotating 
in a current of air. 
THE MEXICAN EARTHQUAKE. 
NOTHER great earthquake has been added to 
the series which has marked the recent increase 
in seismic and volcanic activity along the Pacific 
coast of America. At 11.30 p.m. on Sunday, April 14, 
or about 6 a.m. of April 15 by Greenwich time, the 
greater part of Mexico was visited by a destructive 
earthquake. As usual, the first accounts were not 
only exaggerated, but gave an erroneous impression 
of the distribution of damage; Mexico city, which was 
represented as almost destroyed, proved by later 
accounts to have been comparatively little damaged; 
while the towns of Chilpancingo and Chilapu, as well 
as some others not to be found in ordinary atlases, 
suffered great destruction. The sea-coast towns from 
Salina Cruz to Acapulco suffered severely, and a 
portion of the latter is said to have been submerged. 
The shock is reported as severe at San Luis Potori 
and Juan Batista, though no damage was done at 
either place; these two cities are about 530 miles 
apart and about 350 miles from the region of greatest 
damage, so we may estimate the area over which the 
shock was sensible as extending to somewhere about 
500 miles from the centre of the disturbance. 
The earliest reports stated that railway communi- 
cation between Mexico city and Vera Cruz was sus- 
pended owing to the sinking of the permanent way, 
but this news, which has not been. corroborated in 
later telegrams, is the only suggestion that the focus 
of the earthquake may have extended to any distance 
from the west coast. Everything else points to the 
conclusion that it originated close to the shore-line 
of the Pacific, and was partly, if not wholly, sub- 
marine. Sea-quakes are common in_ this region; 
sometimes they are felt by ships at sea though 
unnoticed on shore, and in at least one instance seem 
to have caused the loss of a ship. The story is a 
remarkable one. On October 3, 1902, the German 
barque Freya cleared from Manzanillo for Panta 
Arenas; nothing more has been heard of the captain 
or crew, but the ship was found, twenty days later, 
partially dismasted and lying on its side. There was 
nothing to explain the condition. of the ship, but a 
wall calendar in the captain’s cabin showed that the 
catastrophe must have overtaken it on October. 4, 
not long after leaving port, as was also indicated by 
the anchor being found still hanging free at the bow. 
Weather reports show that only light winds were 
experienced in this region from October 3 to October 
5, but, on the other hand, severe earthquakes were 
felt at Acapulco and Chilpanzingo on October 4 
and 5, one of which probably caused the damage to 
the Freya which led to its abandonment. 
Prominence has been given in the daily papers to 
earthquakes in Spain and Italy, which occurred 
shortly after the Mexican one; but they were of an 
order the occurrence of which is too frequent to 
justify any direct connection between them and the 
greater one. It may be different as regards the other 
two large earthquakes, which were registered at 
g-10 p.m. on April 18, and at oh. 11 a.m. on April 
Ig; no news of these shocks has yet reached us; they 
must have been earthquakes of the first order of 
importance, but are only known from distant records, 
which are interpreted as showing that they originated 
at about go° from western Europe. This is about 
the distance of Mexico, but it is rare for after- 
NO. 1956, VOL. 75] 
shocks to be of as great magnitude as these; on the 
other hand, it is not uncommon for earthquakes to 
take place in groups, usually originating at nearly 
opposite points in the globe. We may consequently, 
in the absence of news of a great earthquake in 
America or Japan, look for the origin of these two 
earthquakes in the North Pacific Ocean on the eastern 
part of the Malay Peninsula. 
TUBERCULOSIS RESEARCH AND 
VIVISECTION. 
HE investigations conducted by the Royal Com- 
mission on ‘Tuberculosis, contained in a second 
interim report recently issued, would have been 
impossible without the use of experiments on animals, 
and the appearance of this report is most opportune, 
for, almost simultaneously, the Royal Commission 
on Vivisection has published the first volume of the 
minutes of evidence talen before it. 
As regards the investigations on tuberculosis, thirty 
different viruses isolated from cases of tuberculosis 
occurring spontaneously in bovines have been studied, 
and the results of introducing them into a number 
of different animals by feeding and by inoculation 
are recorded. In calves, inoculation usually results 
in generalised progressive tuberculosis, but the effect 
is somewhat dependent on the dose, i.e. the number 
of bacilli, administered. Feeding, on the other hand, 
usually produces lesions limited to the neighbourhood 
of the digestive tract, which generally retrogress and 
become calcareous. The bovine bacillus, when intro- 
duced into rhesus monkeys or chimpanzees either by 
inoculation or by feeding, induces rapid generalised 
tuberculosis, and considering the close relation that 
exists between the anthropoid apes and man, these 
results are of the highest importance. In pigs 
generalised progressive tuberculosis is readily set up 
both by feeding with, and by the inoculation of, bovine 
bacilli. Goats, dogs, and cats are relatively less 
susceptible, but more or less tuberculous infection 
can similarly be produced in them. On this part of 
the investigation the commissioners remark that the 
bacillus of bovine tuberculosis is not so constituted 
as to act on bovine tissues only, and the fact that 
it can readily infect the anthropoid apes, and, indeed, 
seems to produce this result more readily than in the 
bovine body itself, has an importance so obvious that 
it need not be dwelt on. 
The viruses isolated from sixty cases of the disease 
in man have also been studied, and the results 
obtained show that they may be divided into two 
groups, subsequently referred to as group i. and 
group ii. The bacilli of group i. were mostly 
obtained from cases of abdominal tuberculosis occur- 
ring in children, and the results produced by intro- 
ducing them into animals are identical with those 
produced by the bovine baciilus. The bacilli of 
group ii., obtained from various forms of human 
tuberculosis, grow more luxuriantly in culture than 
those of group i., and inoculated into calves and 
rabbits do not produce the generalised and fatal 
disease caused by the bovine bacillus, but in rhesus 
monkeys and in the chimpanzee set up a general 
tuberculosis. Certain human viruses, differing in 
certain respects from those of groups i. and ii., were 
also met with, and are classed as group iii., but an 
opinion on their significance is reserved for a future 
report. 
The commissioners conclude that the tubercle 
bacillus in its nutritive and reproductive powers re- 
1 Serond Interim Report of the [Royal Commission appointed to inquire 
into the Relations of Human and Animal Tuberculosis, Part i., Report. 
Part ii, Appendix. Vol. iv., ‘‘ Comparative Histological and Bacterio- 
logical Investigations.’ By Dr. Arthur Eastwood. 
