272 Tue Microscope. 
not produced. On examining the worms with the microscope 
this parasite was not found. The life history of Syngamus 
trachealis is as follows: Earthworms containing the embryos 
are eaten by the fowl. The embryos are liberated from the 
earthworm and free their way through into the air sacs, thence 
work their way to the lungs where they pass through the 
nymph stage and acquire sexual maturity. The male and 
female then unite and attach themselves by their sucker-like 
mouths to the mucous membrane of the trachea. Between six 
and seven days are required from its entrance into the fowl 
until its attachment to the trachea. In seven days more the 
eggs within the body of the worm become mature; they are 
coughed up, swallowed by the fowl and pass through it into the 
soil. In three weeks these eggs, exposed to the moisture and 
sun, hatch the embryos, find their way into the earthworm, 
where they remain until picked up by some bird, when the 
above process is repeated. Some years one-half or two-thirds 
the young fowls in some localities are destroyed by the gapes. 
This investigation proves that if young fowls are kept’ from 
eating earthworms that terrible scourage of poultry, the gapes 
will be prevented. 
THE PHENOMENON OF MULTIPLE IMAGE. 
HAVE recently observed that the phenomenon of multiple 
| image may be produced in certain diatoms, notably in Tro- 
ceratium Favus. Dilligent search in such books as are accessible 
fail to give me any information on the subject, or in fact men 
tion it at all. I therefore presume that it is not generally 
known. I suggest that a careful study of the beetles eye and 
the question of optics involved will prove a step towards solving 
the problem of the markings on thediatom valve. If youthink 
the subject of sufficent interest to your readers to publish this 
I shall be glad to hear through the same channel the result of 
their inquiry. K. 
Brooklyn, Nov. 12, 1884. 
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