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NATURE 



{Dec. iz, 1877 



whole course of hydrophobia in the dog is run in from 

 four to eight days, the majority of cases proving fatal 

 about the fourth or fifth day. This short description of 

 rabies or hydrophobia, as it affects the dog, is almost 

 exactly applicable to the disease as it occurs in other 

 domestic animals ; a maniacal excitement and a tendency 

 to injure men and animals with which they come in con- 

 tact being as characteristic of herbivorous animals as it is 

 of dogs, cats, foxes, and wolves. 



Having, then, before us an outline of hydrophobia as it 

 affects the lower animals, let us compare with it the 

 disease as it is observed in man. 



In the first place as to the frequency with which the 

 bite of a mad dog is followed by hydrophobia. No 

 general satement can be made on this matter, as the 

 results vary very greatly according to the part bitten, 

 according to the treatment to which the bitten part is 

 subjected, &c. For instance, bites inflicted upon parts 

 protected by clothing are followed by hydrophobia much 

 less frequently than those in which the hand or face is 

 injured, the poison in the former case being absorbed by 

 the intervening clothing. 



Next, as to the period of incubation. In man this 

 varies even more thaia in the case of the dog ; the 

 majority of cases of human hydrophobia have, however, a 

 period of incubation which varies between thirty and fifty 

 days, though exceptional cases occur in which many 

 months have elapsed between the infliction of the bite 

 and the supervention of the symptoms ; these remarks 

 might be illustrated by reference to cases which have 

 occurred in England, and which have been recorded in 

 the medical journals during the last two years ; the 

 shortest period of incubation observed within this period 

 having been eighteen days, and the longest nine months. 

 During the period of incubation there is nothing to 

 distinguish a bite inflicted by a rabid dog from the bite 

 of a healthy dog. The study of some of the recorded 

 cases of the disease would almost lead to the conclusion 

 that in man there is during the period of incubation a 

 tendency to nervous depression and melancholia which 

 is a precursor of the terrible symptoms which are to 

 follow ; it is obvious, however, that great caution ought 

 to be exercised in the interpretation of such mental 

 symptoms, which are after all in many cases but the 

 necessary and logical results of an injury of which 

 the possible consequences are but too well known and 

 correspondingly dreaded. If we except these symptoms 

 of depression and melancholy there are no characteristic 

 phenomena which intervene between the infliction of the 

 bite and the onset of the attack of hydrophobia. 



In a certain number of cases the advent of the disease 

 is ushered in by pain of a neuralgic character in the 

 bitten part ; this appears to be merely an evidence 

 of the general feeling of illness which then supervenes, 

 rather than any evidence of the specific nature of the bite. 

 More commonly the first phenomena are merely vague 

 symptoms of feeling very unwell, accompanied often by 

 an intense feeling of melancholy. A deep sighing cha- 

 racter of the inspirations, or even paroxysmal attacks of 

 difficulties of breathing, wiih some pain in the throat 

 and pain in the precordial region often follow. Beyond 

 the feeling of impending evil, there is no "mental symp- 

 tom at this stage of the disease at all comparable with 



those observed in the lower animals. Next in the order 

 of accession is the difficulty which the poor patient 

 experiences in swallowing ; this, at first slight, symptor.i 

 soon acquires a terrible intensity ; the patient is troubled 

 by an agonising thirst, and yet dares not drink ; an} 

 attempt to drink gives rise to a terrible spasm of the 

 muscles engaged in deglutition, and apparently to a 

 simultaneous spasm of the muscles engaged in inspiration 

 so powerful that he dreads suffocation. An analysis 

 of the symptoms at this stage leads one, indeed, to the 

 opinion that swallowing is often dreaded because of, and 

 is indeed impeded by, the spasm of the inspiratory 

 muscles which it induces. Then follows a stage in which" 

 often, though by no means invariably, the patient becomer 

 subject to delusions, and often violently maniacal, and 

 this is succeeded by a stage of exhaustion and quiet which 

 ushers in the fatal termination. 



If we have sketched with some degree of minuteness 

 the outlines of a very painful picture, we have done so 

 because a knowledge of them was absolutely essential 

 before we could 'attempt to consider what light science 

 has thrown upon this dread disease, and what reliance 

 is to be placed upon the remedies which have been 

 suggested for its cure. 



We shall now, in the first place, consider the results of 

 pathological investigations relating to hydrophobia. Are 

 there not some well marked and constantly present 

 lesions of the great nerve-centres corresponding in some 

 measure to the symptoms which manifest themselves 

 during life t The older observations generally concur in 

 showing that the brain and spinal cord are the seat of 

 congestions which are,however, not sufficiently constant 

 in their localisation to admit of any conclusions being 

 drawn from them. And, since the time when pathological 

 anatomy attained its present development and accuracy, 

 but few persons sufficiently competent to draw accurate 

 conclusions from their observations have had the oppor- 

 tunity of working at the subject. From the observations of 

 Benedict (F^Vr/^ija/'^ Archiv, 1875), it resulted, that in addi- 

 tion to more or less widely spread congestion, there occur 

 granular degeneration of nerve-cells, and of nerve-fibres 

 in various parts of the brain. Subsequently Wassilieff, 

 working under the direction of Prof. Botkin, of St. Peters- 

 burg, described {Centralblait f. d. ined. Wissenschnft, 

 1876, p. 625) a, some alterations in the nerve-cells of 

 the medulla oblongata, the outlines and nuclei of which 

 are indistinct and the contents cloudy ; /5, a large accu- 

 mulation of corpuscles of the size of white blood-cells in 

 the interstitial connective tissue of the brain, in the 

 peri-vascular canals and immediately surrounding them ; 

 and ^, the presence of a highly refracting substance in the 

 peri-vascular spaces, especially in the cortical layers of 

 the cerebral hemispheres. Somewhat akin to them are 

 the observations of Dr. Gowers who found in the medulla 

 oblongata after death from hydrophobia, accumulations 

 of cells, resembling white blood-cells, in the vicinity 

 of the blood-vessels, and [also in the nervous substance. 

 But what do all these observations indicate ? In all 

 probability the accumulations of white cells are caused 

 by the emigration of white blood corpuscles from the 

 blood, so that they are to be held as supporting the older 

 observations which alleged congestions of the brain to be 

 frequently present, and the other pathological changes 



