52 The Natural History of British Game Birds 
with a mass of tape-worms. He advanced the view that the disease was in no way 
due to the presence of entozoa, but that the peritoneal inflammation was the cause of 
death. His conclusions are summed up in these words : " The mortality is, in fact, 
due to malnutrition, to a cachectic state transmitted from parent to offspring, and pre- 
disposing the young to suffer from influences such as severity of seasons or temporary 
scarcity of food, which under other circumstances they would have resisted successfully." 
Thus we see that the tape-worm theory of death was rejected, and that Dr. Young 
expresses the view that the Grouse died of a disease of an epidemic character. 
Mr. H. Hammond Smith in the Field (Aug. 15, 1908) gives a very able summary 
of recent writings on the subject, prior to the report of the Grouse Disease Inquiry 
Committee, and from which I extract the following notes : — 
"The subject of grouse disease will always be associated with the name of Dr. Spencer 
Cobbold, on account of the important work carried out by him in 1872 on the entozoal parasites 
of grouse. In 1873, besides his contribution to the Field of that year, he published a brochure 
on grouse disease, in which he attributed the cause of the malady to a small nematode worm, 
found principally in the blind caeca of the birds, and called by him Strongylus pergracilis. This 
worm was found in large numbers in the specimens examined by him, which also presented similar 
symptoms to those which died of grouse disease, and were described by St. John in 1847. This 
parasitic theory of Dr. Cobbold's must not be confounded with the opinion of Dr. Young, who 
in 1868 rejected the parasitic theory of the origin of grouse disease. Dr. Young referred to tape- 
worms as entozoal parasites, but Dr. Cobbold founded his theory on the presence of the round 
worm, or strongyle, which was apparently not observed by Dr. Young. 
"In the Zoologist for November 1882, Mr J. A. Harvie-Brown published a paper in which 
he attributed grouse disease to over-preserving, overstocking, the indiscriminate destruction of 
vermin, such as the peregrine falcon, &c, the too rapid burning of heather, the eating by the 
birds of heather which had been frosted, and a wholly artificial system of 'grouse farming.' But 
unfortunately he admits that he writes without statistics. On the one hand, he states that disease 
is never seen on the deer forests, where grouse lead a natural, not an artificial, life, while on the 
other hand it is seen on overstocked moors, where there may be 'fifty birds to the acre,' although 
on this point again he had no statistics, and in reality nothing like it exists. 
"The danger of overstocking is really a remote one on well-kept moors. Look at the large 
bags obtained on the Rimington moors, where disease is practically unknown. A moor that at 
the end of the season has produced one brace of grouse to every ten acres is a good moor, and that 
cannot be called overstocking. 
" Mr. D. G. Macdonald, in his book on grouse disease (1883), gives a very interesting account 
of disease as observed on two moors in the north of Scotland, and also refers to an article in Bell's 
Life of June 16, 1861, on disease among the grouse of British Columbia and Vancouver Island. 
The Indians of those parts state that when the winter has been more than commonly severe and 
the spring cold, the leaves and buds of the trees and shrubs on which the grouse feed lack the 
nutrition necessary for the health of the birds, and consequently a disease is germinated among 
them to which they speedily succumb. He also cites two instances in Scotland in 1867, one of a moor 
exposed to the cold wind of spring after a severe winter ; the heather was dry and sapless, and 
during that season there was a great mortality among the grouse, while on a moor near, in the same 
county, but which was very sheltered from the cold spring winds, the grouse season was a very good 
one. He also points out that in the birds examined the liver was black and soft. He further 
mentions a very important fact, namely, that in 1867 many of the birds picked up were plump and 
in excellent plumage, whereas in former years the birds found dead were characterised by dull, 
disordered plumage and attenuated bodies. He evidently thought there were two forms of disease. 
Mr. Macdonald also refers to the periodicity of the disease ; according to his statement disease 
was noted in 1809, 1824, 1835, 1847, 1856, 1865, and 1870. He goes on to say it invariably began 
on the moors furthest south, and travelled northward county after county. 
