156 Rev. Leonard Jenyns’s Description , &pc. 
terally, or further from each other, than those on the dorsal sur- 
face. These perhaps represent the prolegs of other larvae. 
It would be a matter of great interest, as well as importance, to 
ascertain by what means the larvae above described were intro- 
duced into the human body. I regret, however, my inability to 
throw much light on this inquiry. It is observable that the 
symptoms of which the patient complained first showed them- 
selves in the spring of the year, which is the season in which, 
under ordinary circumstances, the larvae would be hatched. The 
larvae were not voided till the summer and autumn following, 
when they appear to have been nearly, if not quite, full-grown. 
Hence it would seem probable that they were conveyed into the 
stomach in the egg state, and that after being hatched, they passed 
thence into the intestines, where they would have no difficulty in 
finding subsistence, if, as De Geer states, they reside naturally, 
during this period of their existence, in the ordure of privies. Dr. 
Bateman seems to have been of opinion, that, in the cases recorded 
by him, the larvae were taken into the stomach with the water 
drunk, or otherwise used by the patient. But I think it question- 
able whether they are likely to occur in water, which was not 
largely mixed up with either decayed animal or vegetable matter, 
and which, from the presence of such impurities, would be scarcely 
used for the purpose above-mentioned. 
I found, also, on making inquiries, that in the case under con- 
sideration, the patient, who has lived in his present house for 
many years, has never drunk water unmixed, but generally beer, 
tea, and such beverages. At the same time it was added, that 
the water used is entirely supplied from a pond on a stiff clay. 
How far the above particulars will enable others to arrive at 
any probable explanation of this occurrence is perhaps doubtful. 
But when combined with the circumstances under which parallel 
cases may be hereafter noticed, they may possibly lead to some 
conclusion of practical utility towards checking so unpleasant a 
source of disorder in the human frame. 
Plate XV. Fig. 1. The larva above described of the natural size. Fig. 2. The 
same seen from above, and magnified. Fig. 3. The same seen from beneath. 
Fig. 4. One of the branchial-like appendages. Fig. 5. One of the supposed 
antennaj. Fig. 6. One of the dorsal tubercles. Fig. 7. One of the spiracu- 
liferous tubercles of the last segment seen laterally. Fig. 8. The same, seen 
from above. Fig. 9. One of the ventral tubercles. 
