JULY 23, 



1891] 



NA TURE 



271 



pairing involves a tacit assumption that the laws of 

 society are at bottom mere formulated instincts ; and this 

 assumption really underlies all our author's theories. His 

 fundamental position compels him, if he will be con- 

 sistent with himself, to hold that every institution con- 

 nected with marriage that has universal validity, or forms 

 an integral part of the main line of development, is 

 rooted in instinct, and that institutions which are not 

 based on instinct are necessarily exceptional, and unim- 

 portant for scientific history. One does not expect a 

 tacit assumption to be carried out with perfect consist- 

 ency ; but, oil the whole, Mr. Westermarck's results 

 correspond with his assumption, and have no evidence to 

 satisfy anyone that is not prepared to share the assump- 

 tion with him. 



To show this at length would exceed the limits of a 

 short review ; let us, however, take, as a crucial test, Mr. 

 Westerm;irck's explanation of the origin of exogamy. He 

 believes that exogamy and all laws of incest originate in 

 an instinctive aversion to sexual intercourse between 

 persons living closely together from early youth (p. 320), 

 and the origin of this instinct he explains as follows. He 

 thinks it can be proved that consanguineous marriages 

 are detrimental to the species. Now, 



" among the ancestors of man, as among other animals, 

 there was, no doubt, a time when blood-relationship was 

 no bar to sexual intercourse. But variations, here as 

 elsewhere, would naturally present themselves ; and 

 those of our ancestors who avoided in-and-in breeding 

 would survive, while the others would gradually decay 

 and ultimately perish. Thus an instinct would be deve- 

 loped which would be powerful enough, as a rule, to pre- 

 vent injurious unions. Of course, it would display itself 

 simply as an aversion on the part of individuals to union 

 with others with whom they lived ; but these, as a matter 

 of fact, would be blood relations, so that the result would 

 be survival of the fittest " (p. 352). 



The obvious and fatal objection to this theory is that it 

 postulates the existence of groups which through many 

 generations (for the survival of the fittest implies this) 

 avoided wiving within the group. And this is, in fact, a 

 well-established custom of exogamy, so that the theory 

 begins by postulating the very custom that it professes 

 to explain. Moreover, it is questionable whether Mr. 

 Westermarck's theory even helps to explain the wide 

 diffusion of exogamy. For where wiving outside the 

 local group is the rule, all neighbouring groups mingle 

 their bloods, and consanguineous marriages are not 

 escaped. 



It is not surprising that Mr. Westermarck, with his 

 habit of looking at the whole subject from a biological 

 point of view, should have little sympathy with the specu- 

 lations of a man like McLennan, to whom marriage is 

 not a mere fact of natural history, but a relationship 

 resting on contract and approved by custom or law ; and 

 who in all his investigations gives weight to the action of 

 human intelligence as the decisive factor in social pro- 

 gress. But it is a pity that this lack of sympathy has 

 sometimes prevented our author from appreciating the 

 full scope of McLennan's methods and arguments. What 

 is said about the Levirate at pp. 510-14 could not have 

 been written if Mr. Westermarck had carefully read the 

 discussion of the subject in " The Patriarchal Theory" ; 

 nor, to mention a trivial matter, would he in that case 

 NO. I 1 34, VOL. 44] 



have made the error of confounding the Hindu Levirate 

 with the Nyoga (p. 514, «<?/^). And here I may also note 

 that the criticism of McLennan's views of exogamy does 

 not ta'<e account of the posthumous and very important 

 paper published in the English Historical Review for 

 January 1888. 



These are details : what is more to be regretted 

 is that Mr. Westermarck has not learned, as he might 

 have done from McLennan, a sounder method of handling 

 the evidence drawn from the usages of rude societies. 

 The very possibility of reconstructing the history of 

 human progress rests on the fact that all over the world 

 mankind has been moving in the same general direction, 

 but at very various rates, and that careful reasoning, 

 aided especially by the observation of cases which exhibit 

 a state of transition {e.g. from one type of kinship to 

 another), enables us to bring out the order in which the 

 various observed types of social structure succeed one 

 another. Of all this, Mr. Westermarck does not seem to 

 have the le ist idea. He collects facts about the prevalence 

 of kinship through males or through females, about for- 

 bidden degrees, and so forth, without ever rising to the 

 conception that the evidence is good for anything more 

 \.\i2C!\ 2lX\. inductio per enumerationem simplicem. This is 

 not the way in which real progress can be made. 



W. Robertson Smith. 



OUR BOOK SHELF. 



Geological Map of Monte Somma and Vesuvius. Con- 

 structed by H. J. Johnston-Lavis, M.D., M.R.C.S., 

 B.-es-Sc.,F.G.S.,&c., during the Years 1880-88. Scale, 

 I : 10,000 (6"33 inches = i mile). In Six Sheets, with 

 a Pamphlet entitled " A Short and Concise Account 

 of the Eruptive Phenomena and Geology of Monte 

 Somma and Vesuvius." (London : George Philip and 

 Son, 1891.) 

 During the latter half of last century, the changes 

 taking place in Vesuvius were carefully studied and faith- 

 fully chronicled by an English diplomatist — Sir William 

 Hamilton ; in the closing years of the present century, 

 the famous volcano has found an equally indefatigable 

 investigator and historian in the person of an English 

 medical man resident in Naples — Dr. Johnston-Lavis. 

 In 1884, Dr. Johnston-Lavis laid before the Geological 

 Society an elaborate memoir, in which he detailed the 

 theoretical conclusions at which he had arrived after long 

 and patient study of the various sections exposed on the 

 flanks of Somma and Vesuvius. He has now published 

 a very valuable addition to this work, in the form of a 

 map constructed on the basis of the topographical sur- 

 veys of the Italian Government, and coloured in accord- 

 ance with the views to which he has been led by his long 

 and painstaking geological labours. 



In his general memoir on the geology of Somma 

 and Vesuvius, the author has divided the time covered 

 by the history of the volcano into four " eras," and these 

 again into eight " phases," while some of the latter are 

 subdivided into "periods." In colouring the map, it has, 

 of course, not been found possible to give expression to 

 anything like such a minute classification of the rocks 

 composing the mountain as is impliel in such a scheme. 

 The legend on the map recognizes as the great landmarks 

 in the past history of the volcano the paroxysin of 79 a.d. 

 and the great eruption of 1631. The pamphlet accom- 

 panying the map, however, gives a very useful and read- 

 able abstract of the earlier memoir ; and the map and 

 descriptive pamphlet together cannot fail to prove of the 

 greatest service to all students of vulcanology. By their 



