August 13, 1908] 



NATURE 



34: 



'illE GROUSE-DISEASE REPORT. 



\\J E are indebted to the secretary for an advance 

 '' • copy of an interim report, issued by the Board 

 of Ag'riculture and t'isheries lor Scotland, of tlie Com- 

 mittee on the Grouse-disease Inquiry appointed in 

 1905, with Lord Lovat as chairman. It should be 

 stated at starting that althoug-li this committee was 

 appointed by Lora Onslow, no Government funds were 

 allocated tor its use, in consequence of which the 

 entire expense has hitherto been defrayed by private 

 subscriptions, of which a list is given in the docu- 

 ment before us. 



F'rom one point of view, the committee has been 

 decidedly unlucky in that during the period of its 

 investigations no cases of the acute, or epidemic, phase 

 of grouse-disease have come under its notice. In 

 these circumstances, to say nothing of further investi- 

 gations required in connection with the chronic, or 

 endemic, phase, the work accomplished cannot be 

 regarded as in any way approaching finality. Neverthe- 

 less, the committee (and we think rightly) decided to 

 issue the interim report now before them, if only for 

 the purpose of informing subscribers what has been 

 already done, to point out the lines of future in- 

 vestigations, and, above all, to endeavour to obtain 

 additional funds, without which the inquiry cannot be 

 much further continued. 



.'Vs pointed out in a covering letter from the secre- 

 tary, there is naturally considerable difficulty in issu- 

 ing a very instructive report in the middle of an 

 inquiry. Many important questions are still under in- 

 vestigation, and even where apparently definite results 

 have been obtained, it has been deemed undesirable 

 to publish these until they have been fully verilied. 

 Nevertheless, there is a wealth of most important and 

 valuable information in the document, and the com- 

 mittee is to be congratulated on having apparently 

 identified the cause and nature of the chronic phase 

 of the disease. In the course of the inquiry reports 

 have been drawn up dealing with bacteriology, the 

 causes of mortality in specimens submitted for ex- 

 amination, the economic value of the grouse-shootings 

 in Great Britain, and heather-burning. These and 

 other reports are held over for the present, but will 

 form part of the final report of the committee. 



.Although great caution is displayed in giving any 

 statement as final, it is pointed out in connection with 

 the chronic disease that it appears to be a wasting, and 

 usually fatal, illness, in which the parasitic intestinal 

 worms affecting grouse at all ages and all seasons 

 attain, probably owing to lowered vitality on the part 

 of their hosts, an abnormal development, and are thus 

 enabled to react injuriously on the bird's general 

 health and condition. The most easily recognised 

 symptoms are loss of weight, redness and acute con- 

 gestion of the interior of the long blind-appendages 

 (caeca) of the intestine, and an irregular moult and 

 slow subsequent re-feathering, resulting in bare legs 

 and a poor and dingy condition of the plumage. 



The latter features, as pointed out bv P*Ir. E. A. 

 Wilson, the field-naturalist to the committee, in a 

 separate section of the report, must not, however, by 

 any means be regarded as absolutelv diagnostic of 

 the disease. They may, and frequently do, occur in 

 a bird the moult of which has been delayed, and the 

 recovery of which from the effects thereof has been 

 slow. Such birds display the same appearance of duskv, 

 faded plumage and bare legs and toes common to 

 the majority at ai, earlier stage of the season (when 

 they do not come under the ken of sportsmen), and 

 likewise to birds afflicted with the disease. 



In the earlier stages the grouse is less strong on 

 the wing than ordinarily, and changes its station 



NO. 2024, VOL. 78] 



from the heather to the green ground; in many cases 

 the feathers lose their freshness, while a tape-worm 

 may frequently be seen hanging from the vent as the 

 bird rises. In the later stages the power of flight is 

 lost, the congestion of the intestine becomes still 

 more acute, tape-worms are frequently expelled with- 

 out the slightest beneficial effect, while both blind- 

 appendages absolutely swarm with microscopic thread- 

 worms. Loss of weight makes itself daily more 

 noticeable, and the bird mopes about the banks of 

 the stream until death puts a term to its sufferings. 



The tape-worms have, apparently, nothing to do 

 with the disease, being expelled merely on account of 

 the abnormally irritable condition of the intestines. 

 1 he real offender seems apparently to be the thread- 

 worm, Trichostrongylus pcrgracilis, with which, as 

 already mentioned, the inflamed cascaX appendages are 

 crowded. This provisional conclusion is supported by 

 the fact that while in other animals tape-worms do not 

 generally give rise to fatal diseases, thread-worms 

 certainly do so, as in the case of the miner's worm. 



The report next takes into consideration the epidemic 

 or acute phase of the disease, which, as mentioned 

 above, the experts of the committee have hitherto had 

 no opportunity of examining. It is true, indeed, that 

 birds in full plumag'e and of normal weight have been 

 sent in as examples of mortality due to the acute 

 phase, but these, on examination, proved to have 

 died either from the ordinar\' wasting disease or 

 from the effects of accident. 



The external signs of this disease are stated to be 

 that the birds succumb rapidly, without loss of weight 

 or deterioration of plumage, while the local action 

 of the disease is reported in many cases to be intense. 

 Post-mortem examination is stated to reveal patchy 

 congestion of one or both lungs, comparable to the 

 " hepatisation " of tissue occurring in undoubted pneu- 

 monia. The internal organs generally are also stated 

 to be congested, and to exhibit other symptoms of 

 acute and rapidly fatal fever. 



By Prof. Klein this phase of grouse-disease was 

 considered to be an acute form of infectious pneu- 

 monia, due to the presence of parasitic organisms 

 probably belonging to the " colon " group, these being 

 chiefly found in the lungs of infected birds, although, 

 at any rate after death, they might occur in other 

 organs. 



The committee, without wishing to undervalue the 

 evidence of a specialist of Klein's reputation, or the 

 testimony of naturalists and keepers generally, re- 

 marks : — 



" Klein's organism belonged to the widely distributed 

 colon group, and, according to the limited cultural and 

 morphological tests then used, differed in no way from 

 other organisms of the colon group found in the grouse. 



" Members of the colon group, apparently culturally and 

 morphologically identical with Klein's organism, can be 

 isolated from the heart, blood, lungs, and liver of both 

 healthy and emaciated grouse that fiave been dead for a 

 period of from twelve to twenty-four hours, the actual time 

 varying with such factors as temperature and moisture. 



" With regard to keepers' evidence and statements that 

 birds die in full weight and plumage, it must be placed on 

 record that already several times during this inquiry the 

 acute form of grouse-disease with full-feathered birds of 

 good weight has been reported, but in each case examina- 

 tion by the committee's experts has shown that the bird 

 died only from the wasting disease, or as the result of 

 accident. 



" While it is not argued from the above that only one 

 form of disease exists, it is, however, a fact not without 

 significance that in the years 1905, 1906, and 1907 no 

 instance of the acute pneumonic form of grouse-disease 

 has come to the notice of the committee, tliough that com- 

 mittee has had field-observers, 283 local correspondents, as 



