440 



NATURE 



{March 8, 1888 



A Green Sun. 



I WAS looking, a few days ago, at three o'clock in the after- 

 noon, towards the sun, which was shining in a clear sky. 

 Exhaust-steam from an engine employed in the new Thames 

 Tunnel works, and situated just below my window, was passing 

 intermittently over his face. Many puffs had already crossed it, 

 some partially, others completely obscuring the luminous disk, 

 when presently, three puffs, following each other quickly, succes- 

 sively covered the sun, which then shone brightly through the 

 steam with a vivid light-green colour. The effect was strikingly 

 noticeable, and the green colour intense. I watched for twenty 

 minutes, but in vain, for another "green sun," and at 3.30 

 clouds came up. 



I have since tried to reproduce the same effect by observing 

 the arc lights in Cannon Street Station through steam rushing 

 upwards from the safety-valve of a locomotive. Seen through 

 the thickest part of such a column of vapour, the electric light 

 exhibits a deep red colour, and I think there is a green trans- 

 mission near the edge of the column ; but the latter was unsteady, 

 while the point is evidently critical, and it is impossible to say 

 positively that it was so. I). Pidgeon. 



Holm wood, Putney Hill, February 11. 



RABIES AMONG DEER. 



THAT all domesticated or semi-domesticated mammals 

 succumb to inoculation with the virus of rabies 

 has long been asserted, and examples of its occurrence 

 have been duly recorded. The possibility, however, of the 

 disease affecting half-wild animals seems to have been 

 lost sight of, and it was therefore with much surprise on 

 the part of the public that the announcement was received 

 last year of the deer in Richmond Park being attacked 

 by the malady. 



Apart from the general interest attaching to the welfare 

 of the public using the parks in which these animals are 

 kept, and beyond the special interest felt by the veterinary 

 profession in the clearing up of the diagnosis of this 

 strange and novel condition, the outbreak was of import- 

 ance as affording a fresh opportunity of investigating the 

 character of the malady under, as it were, new circum- 

 stances, and hence we find in the reports of this epizooty 

 recently furnished to the Privy Council by Mr. Cope and 

 Prof. Horsley, many points which fill up certain blanks in 

 our scientific information on the subject. 



The prevention of rabies in all animals we have shown 

 before to be the simplest task imaginable for the health 

 authorities of this country to undertake, and nothing 

 illustrates this more clearly than the history of the recent 

 epidemic, which attracted so much notice on account of 

 its excessive mortality, and which terminated by causing 

 the local mischief which forms the ground of this article. 



It will be remembered that in 1884 rabies began to in- 

 crease in the London and home counties districts. No 

 notice being taken of its spread, it soon produced a severe 

 effect, when in 1885 the numerous deaths (twenty-seven) 

 among human beings caused a popular panic, and led the 

 authorities to institute measures for its repression. The 

 authorities in the London district having provided for the 

 merciful extirpation of stray dogs, the familiar vehicle of 

 the disease, secured the non-transmission of the virus by 

 enforcing the use of muzzles. The result of their work 

 during 1886 has been seen during 1887, in the practically 

 total immunity of the population of this great city from 

 this the most justly dreaded of all diseases. Let us not for- 

 get to add in passing that as was pointed out at the time of 

 the expiration of the local regulations by those acquainted 

 with the malady, that the measures being but local could 

 only produce a temporary relief from the evil, since the 

 metropoHs was continually being infected from districts 

 beyond the reach of the regulations, and that though it 

 could be kept free for a time, yet reintroduction of the 

 virus would certainly occur, and the work would have to 

 be done all over a^in. This is actually now happening, 



though not yet officially declared. The disease has re- 

 appeared (as it has usually done) in the southern suburbs, 

 and is gradually making its way into the metropolis. 



But to return. The epidemic of 1885 terminated in the 

 London district with the infection of the roe deer in Rich- 

 mond Park, resulting in the extermination of several 

 hundreds of these valuable and pretty animals. From 

 Mr. Cope's interesting report it appears that the first to be 

 seized was a doe which had a suckling fawn, and as we 

 learn from the very valuable evidence of Mr. Sawyer, the 

 head-keeper of the Park, it seems that under these cir- 

 cumstances a doe will attack a dog attempting to worry 

 the herd, as a rabid dog passing through the Park would 

 do. Fortunately in the Richmond case no instance 

 occurred of the transmission of the disease from the deer 

 to man through the dog as in an outbreak recorded in 

 1856 at Stainborough. Had this happened, the deaths of 

 the deer would not have been attributed to various causes, 

 poisoning, &c. , as they now were until the remarkable aggres- 

 siveness of the affected animals led to a thorough investi- 

 gation by the veterinary advisers of the Government. Rabid 

 deer were sent for observation to the Veterinary College, 

 and the symptoms noted. The exact determination yet 

 remained to be made, and, thanks to the recent researches 

 of M. Pasteur, this was now possible. Portions of the central 

 nervous system from these anin;als were sent to the Brown 

 Institution, and there inoculated by Prof. Horsley into 

 rabbits by the subdural method. These animals died 

 after exhibiting the characteristic symptoms of rabies, 

 and after death the usual post-mortem appearances were 

 duly discovered. More infected deer were sent also to 

 the Brown Institution, and the extraordinary changes 

 effected by the disease more closely studied. This 

 kind of deer, naturally gentle and timid, was trans- 

 formed into a fierce and savage animal, rivalling 

 the rabid horse almost in its attempts to do mischief. 

 The early symptoms, as in all animals, appear to have 

 been indicative of mental hallucination, for the animals 

 would stop feeding, hold up their heads, sniff the air, 

 and then, without the slightest reason, burst into a gallop. 

 When placed in confinement the least noise attracted 

 their attention, and later — i.e. on the second and third 

 day— caused them to charge in the direction of the sound. 

 The mental perversion which leads a rabid dog one 

 moment to lick with almost frantic energy a healthy dog 

 placed with it, and then the next moment to violently bite 

 it, finds its parallel in the deer similarly affected, for these 

 animals in a like manner licked their companions, and 

 then ferociously attacked them, seizing them with their 

 jaws (usually about the shoulders) and tearing off hair and 

 pieces of skin. The points thus inoculated with the virus 

 after cicatrization became, as is almost invariably the 

 case, the seat of intense irritation when the disease 

 actively showed itself; hence one of the most prominent 

 signs presented by the animals was that of their rubbing 

 themselves with such force as to make these parts raw. In 

 connection with the differences which are now known to 

 be characteristic of the same disease in different classes 

 of animals, it is interesting to note that in all large animals, 

 whatever be the previous temperament, the course of the 

 malady is closely identical ; thus in the horse, the ox, the 

 sheep, the pig, the deer, &c., the illness is rapid, there is 

 great aggressiveness, and yet early paralysis. It is of 

 common knowledge that in the dog these two latter 

 features are sometimes widely separated. The paralysis 

 may set in so soon as to obliterate aggressiveness, and 

 thus a distinct form (dumb) of rabies be produced, 

 though of course the aggressive form of the disease always 

 ends in paralysis if not suddenly arrested by syncope. In 

 the deer the combination of the two symptoms seems to 

 have been very equal. For even when the animal had 

 fallen down from paresis (of the hind -limbs more 

 especially) it would nevertheless spring up and attempt 

 to seize and worry with its teeth every person or object 



