tcith Report on Experiments. 
375 
•or husk-strongyle {Strongylus micrurus) require a change of 
hosts in order to arrive at the larval state. After their passive 
transference to the bodies of earth-worms, and subsequent 
escape into the soil, they undergo important changes ; more or 
less moisture being in all cases necessary for their growth in 
the free state. What may be called the penultimate stage of 
life having thus been arrived at, it becomes more than probable 
that the final passive introduction of the worms into the lungs 
of the calf is accomplished during the act of feeding. In short, 
the young worms commonly gain access to their victims either 
with fresh-cut fodder obtained from low-lying pastures, or from 
the grass of swampy grounds, or, it may be, occasionally, from 
stagnant pond -water itself, so that in one or other of these ways 
the accomplishment of their ultimate destiny is amply secured 
The organisation of the strongyloid larva; is already so con- 
siderably advanced during fifty or sixty hours' freedom in dew 
or water, that when once they have been conveyed to the lungs 
it is evident that only a very few days' sojourn within their 
victims is all that is necessary in order to enable the young 
worms to arrive at maturity. In other words, about a week, or 
even less, will be sufficient for them to acquire their definitive 
sexual form, size, and other adult characters. 
Practical Considerations and Suggestions. — One of the first 
questions likely to arise in the mind of the agriculturist is as 
to whether the foregoing facts throw any light upon his past 
experiences of the lung-disease of animals. Admitting that 
further scientific investigations are desirable, I would in the 
meantime draw attention to a few of the remarkable statements 
that have been made by trustworthy persons. At a meeting 
of the Quekett Microscopical Club, during my Presidency, 
Mr. Beulah (whose name has already been mentioned, and 
who farms at Brigg, Lincolnshire) stated that, of a flock of 
72 sheep, all but two were on a particular day sent to graze on 
a meadow that proved to be a source of infection. The entire 
70 grazing animals took the parasitic lung-disease, due to 
Strongylus filaria, and all of them died. The two animals that 
were not put into the field remained perfectly well. These 
facts were sufficiently interesting in themselves ; but the most 
remarkable circumstance was that, when Mr. Beulah examined 
the dew on the grass where the animals had been grazing, he dis- 
covered that the moisture contained quantities of minute nema- 
toid worms. Unfortunately, no specimens were preserved, so we 
cannot institute any comparison between INIr. Beulah's " finds " 
and the free larvae reared by my experiments. If, as appears 
to me probable, the little nematoids discovered in the pasture 
were juvenile examples of the lung-worm of the sheep, they 
