LETTER FROM FORT McKAVETT. 103 
M. Wroblewski, a young Polish chemist, has succeeded in liquifying oxygen 
gas He produces the most intense cold as yet known, by boiling ethylene in 
vacuum, and then submitting oxygen to a pressure of 22 atmospheres, when the 
gas assumes a liquid form and is perfectly colorless, thus differing from ozone, 
which is blue. He has been equally successful with nitrogen. 
Dr. Jules Guerin has performed some brilliant surgical operations, by employ- 
ing caustics to destroy sensibihty round the parts diseased. The caustic formed 
a skin wholly impervious to the fluids of the ulcers at the same time. 
LETTER FROM FORT McKAVETT. 
Robert Robinson, Esq., who lives near Fort McKavett, Texas, has furnish- 
ed me some interesting facts that have come within his knowledge, in reference 
to centipedes and tarantulas. One evening in 1861, while living in the house 
now occupied by Major Jewett, he was leaning against the outside wall of the 
house, while standing on, the veranda, when he felt something crawUng over his 
hand as it rested against the wall. Springing away he got a lamp, and found it 
was an immense centipede. Taking the tongs he caught the centipede and 
put it into an empty glass jar, and placed it on the mantel. The centipede was in 
■continuous motion day and night, but could not get out of the jar, although left 
uncovered. About three days afterward some member of the family caught an 
ordinary sized mouse, and Mr. Robinson put him into the jar with the centipede. 
When the mouse was introduced the centipede backed up and humped himself, 
as a cat sometimes does before it springs on its prey, and then seized the mouse 
with his forceps by the head between the eyes and ears, and crunched him 
down head foremost, the mouse entirely disappearing in twenty seconds by the 
second-hand of the watch. During this process the centipede showed his in- 
cisors like those of the fish head. 
About two weeks after this, he caught a horned frog, and placed him in the 
jar with the centipede. The frog jumped about all night in the jar which was 
covered now, and there was a terrible racket, a kind of pounding, in the jar. In 
the morning Mr. Robinson took the jar out into the yard, and emptied it on the 
ground. The frog went off apparently uninjured, but the centipede gasped three 
times and died. He then measured the centipede, and found that he was ten 
inches and a half in length, a mammoth centipede for this locality. He had no 
alcohol, and as it cost about $20 a quart, he concluded not to preserve the speci- 
men. The horned frog was undoubtedly protected in the terrible contest, from 
the poison of the centipede, by its hard thick skin which serves as a kind of 
armor. 
Mr, Robinson has caught centipedes three inches in length, and thrown 
them into the nests of the fierce red ants wlmch build houses of sand and gravel 
here. The ants would immediately cover them all over and bite off the legs of 
