556 



NATURE 



[April 14, 1892 



And after showing how this impulse of joy is mani- 

 fested in different animals according to their peculiarities 

 of structure and habit, and after giving a number of other 

 illustrative cases, he thus concludes : — 



" I am convinced that any student of the subject who 

 will cast aside his books, and go directly to Nature to 

 note the actions of animals for himself — actions which, 

 in many cases, appear to lose all significance when set 

 down in writing — the result of such independent investi- 

 gation will be a conviction that conscious sexual selection 

 on the part of the female is not the cause of music and 

 dancing performances in birds, nor of the brighter colours 

 and ornaments that distinguish the male." 



Other chapters of almost equal interest are those on 

 the habit of the huanaco to go to certain places to die, 

 and on the strange instincts of cattle, such as the excite- 

 ment caused by the sight and smell of blood, that pro- 

 duced by scarlet clothing, and the persecution of the sick 

 and weakly of the herd. These subjects are discussed 

 with a fulness and originality the result of long personal 

 observation, and will command the careful attention of 

 those who are interested in the mental phenomena pre- 

 sented by animals. It remains only to add that the book 

 is beautifully got up, that the text is singularly free from 

 misprints, and that the numerous illustrations — photo- 

 graphic reproductions of drawings — are at once delicate 

 and characteristic. Never has the present writer derived 

 so much pleasure and instruction from a book on the 

 habits and instincts of animals. He feels sure that it 

 will long continue to be a storehouse of facts and obser- 

 vations of the greatest value to the philosophical 

 naturalist, while to the general reader it will rank as 

 the most interesting and delightful of modern books on 

 natural history. Alfred R. Wallace. 



THE PREVENTION OF INFLUENZA. 

 A Study of Influenza^ and the Laws of England con- 

 cerning Infectious Diseases, Qr^c. By Richard Sisley, 

 M.D.Lond., M.R.C.P.Lond. (London : Longmans, 

 Green, and Co., 1892.) 



UNDER the above title Dr. Sisley has collected 

 papers read by him during the past twelve months 

 before the Society of Medical Officers of Health, the 

 Epidemiological Society, and the Congress of Hygiene. 

 To these are appended extracts from the different Acts 

 bearing on infectious disease, the provisional memoran- 

 dum on epidemic influenza just issued by the Local 

 Government Board, and sundry other matters connected 

 with the subject. The work makes no pretence to be a 

 study of influenza from the clinical or pathological stand- 

 point ; it deals simply with the prevention of the disease 

 in epidemic form, and the legal machinery at our command 

 for that purpose. 



It may, at first sight, seem strange that, when, during 

 the latter part of 1889, we watched the epidemic wave 

 sweeping gradually over Europe towards our own shores, 

 no one dreamed of taking any action with a view to 

 staying the plague. But we must remember that it was a 

 disease new to the modern generation of physicians — a 

 disease with which the sanitary science of the present 

 day had never had to cope — a disease whose cause was 

 wholly unknown, and whose infectious character was 

 imperfectly recognized, or even denied. Two years and 1 

 NO. I 172, VOL. 45] 



more under the yoke have given only too abundant 

 opportunity to investigate it from every point of view, 

 and it is not too much to say that the Local Government 

 Board Report by Dr. Parsons, issued last year, contains 

 the most admirable and exhaustive study of influenza 

 which has appeared in any European language. Yet the 

 actual nature of the virus remains still an only partially 

 solved problem : bacteriological research points to a 

 definite bacillus as the probable organism, but till its 

 natural history has been more thoroughly worked out, 

 we must be content to fight the foe in the dark. 



Dr. Sisley has not reprinted his papers in chronological 

 order, though it is convenient to consider them thus. In 

 that read before the Epidemiological Society in May 

 1891, he treats of the spread of influenza by contagion, 

 strongly advocating the view that this is the most im- 

 portant factor in the diffusion of the disease. He bases 

 his belief on very conclusive grounds, and few will now 

 be found to disagree with him. Dr. Parsons's Report, 

 appearing some time after this paper was read, has so 

 abundantly confirmed the opinion, that it may be trusted 

 that, whatever part seasonal and climatic influences may 

 play as favouring causes, " telluric " theories have had 

 their day. The disease is, in fact, an acute specific fever 

 infectious in a somewhat high degree, and, in virtue of 

 its short incubation period, diffusing itself with unusual 

 rapidity. 



Only an abstract is given of the paper read by Dr. 

 Sisley before the International Congress of Hygiene last 

 August. It deals with the prevention of the spread of 

 epidemic influenza, and advocates general hygienic mea- 

 sures, the possible employment of prophylactics, and 

 especially the avoidance of infection. 



The essence of the book lies, however, in the paper 

 read before the Society of Medical Officers of Health in 

 January of the present year. Here Dr. Sisley discusses 

 the application to influenza of the existing sanitary laws 

 of England, and it cannot be said that his conclusions 

 are of a very reassuring character. It is instructive to 

 observe that the difficulty lies in this — that nobody knows 

 whether influenza is a " dangerous infectious disease " 

 within the meaning of the Acts, or not. Common-sense 

 might have supposed that a disease which the Registrar- 

 General declares to have been directly or indirectly re- 

 sponsible for some 27,000 deaths in England and Wales 

 in a single year, would not inaptly be described as 

 dangerous ; but the point has not as yet been settled 

 in a court of law, and it is possible that legal opinion 

 might take a contrary view. Should its dangerous cha- 

 racter be upheld by law as well as medicine, the provinces 

 have at least the Public Health Act of 1875 to fall back 

 on, and can thus enforce isolation of early cases. 

 London, under its new Act, is apparently helpless ; and, 

 as it would take twelve days to add influenza to the list 

 of notifiable diseases, it is clearly unwise to wait for a 

 fresh outbreak before taking such a step, if it be deter- 

 mined to take it at all. It cannot be doubted that 

 efficient isolation of early cases would be the most im- 

 portant method of averting an epidemic ; the difficulty 

 lies in a matter which Dr. Sisley has not dealt with — 

 namely, the diagnosis of such cases. Medical men now 

 recognize as slight instances of epidemic influenza cases 

 which in non-epidemic times would be passed over as 



