208 Interim Report on Veterinary Investigations. 
they as parents give birth. Of late years the disease has been 
largely on the increase, from causes which are but imperfectly 
understood, and which it would seem can only be elucidated by 
further investigation into the natural history of the worm. So 
far as the structure and means of direct propagation of the para- 
site are concerned, there appeals to be but little to add to our 
present knowledge. The researches into its natural history, as 
far as they have gone, would, however, seem to lead to the con- 
clusion that the young, or embryotic, worms are fitted for pro- 
pagation of their species to a great extent rather out of, tlian 
within, the air passages of the animal. 
Indeed it may hereafter be shown that it is essential to the 
ultimate sexual development of the worms, that in their immature 
condition they should become parasitic to some of the grasses, 
natural and artificial, on which the lambs are fed at the time 
of being attacked. With a view to assist in this part of the 
inquiry, I have asked for and received portions of turf cut from 
meadows on which diseased lambs had been pastured. These 
turf-cuttings have been supplied by two members of the Lincoln- 
shire Committee, and will, as soon as the season is more advanced, 
be subjected to a searching microscopical examination. 
With the same object in view, a series of questions — see Ad- 
dendum — has been drawn up and forwarded to the Secretary of the 
Lincolnshire Society for circulation among the members. In due 
time they will be answered and returned to me for analysis and 
deduction. 
It may further be remarked that, as negative evidence may 
not unlikely prove of great value in the inquiry, I have repeated 
an experiment — some years since adopted by me — namely, that 
of conveying the ova of the worm, and also embryotic worms 
obtained from the lungs, directly into the air passages of a Iamb. 
On former occasions, experiments of the kind have invariably 
had a negative result ; and the present one does not promise any 
other, as the lamb — the subject of the experiment — appears to 
continue in perfect health. The introduction of the ova and young 
worms has been twice had recourse to ; first, on October 24th ; 
and secondly, on November 17th, 187L An inquiry, of this 
kind must necessarily occupy much lime and attcntitm and pro- 
bably the carrying out of numerous exjieiinients on selected 
farms, .as well as within an institution like the Royal Veteri- 
nary College. The subject, however, will receive every attention, 
and no time will be lost in its fuither investigation. 
Fd>. l8t, 1872. 
