PARASITES OF ANIMALS. : ash 
The septic element disengaged from these putrid fragments 
retarded the development of the strongyli, but failed to arrest 
it. And even if the experimental troughs contained a very 
large amount of water, the strongyli disengaged themselves 
in great numbers from the morsels of putrid lungs; and, 
though reduced to a putrid pulp, the eggs could be seen 
amidst this ready to open, and the young worms escaping 
from their envelopes.” 
“Tt is in fresh water that the worms are most readily devel- 
oped, and live longest after leaving their natural habitat. 
Water is a transition medium in which the worm which has 
abandoned one animal can survive, waiting a favorable oppor- 
tunity to enter another. In this medium the strongyli are 
hatched and live for entire weeks and months without percep- 
tible growth, that is to say, they preserve their primary mi- 
croscopic proportions. They can there resist sudden changes 
of temperature and the deleterious influence of putrid matters, 
whilst they wait an occasion of entering with the aliments into 
the body of a new host, in whose air passages they find the 
conditions necessary to their assuming the attributes of sexu- 
ality and reproducing their kind. 
Causes.—These are, of course, primarily and mainly the 
introduction of the embryo strongyli into the system, but 
many other conditions may combine as accessory to the pres- 
ervation and propagation of the worms. Thus, wet seasons, 
by providing moisture or pools for the preservation of the em- 
bryos, contribute to their wider diffusion. In keeping with 
this we find the first record of the disease as existing in the 
low wet grounds of Holland, and the two by Despallens as 
occurring in the wet summers of 1795 and 1811. The same 
holds good in England alike as regards the prevalence of the 
‘disease in the low fenny counties, and in rainy seasons; and 
these remarks apply to other animals as well as calves and 
lambs. A donkey, from the low meadows at Hammersmith, 
. London, rarely failed to yield a supply of the strongyli. And 
in the present year, which has proved unusually cold and wet 
in the British Isles, we are not surprised at the serious com- 
plaints of the extraordinary death of pheasants from gapes. 
