SCIENCE. 



[Vol. XVIII. No. ^44 



within fifty yards of the house was struck, the upper pai-t of the 

 trunk and several of the branches to the end being stripped of 

 their bark, but the lower part of the trunk showing no sign of 

 passage of the lightning. Thomas Darley. 



York, England, July 31. 



That Hessian Fly Parasite. 



The item concerning the introduction of a European parasite of 

 the Hessian-fly into this State which is going the rounds of the 

 press, and which I notice you have copied in your issue of July 

 17, was unauthorized, and is in some respects inaccurate. 



The parasites were not obtained originally from the Smithsonian 

 Institution, but were sent me by Dr. Riley, the entomologist of 

 the United States Department of Agriculture, several other ento- 

 mologists, as I understand, having received them at the same time. 

 This was, in short, an experiment of the Division of Entomology, 

 and not my own. 



The parasite is Semiotellus nigripes, and, like our native species 

 of the same genus, infests the larva, not the egg. 



S. A. Forbes. 



Champaign, III., July 20. 



Information Wanted. 



Can I learn through the columns of Science how to interpret the 

 indications of the thermometer with bulb blackened and inclosed 

 in an exhausted glass case ? 



Are there any accepted formulse for this so called solar radiation 

 thermometer, and where can one find the literature of the sub- 

 ject f F. C. Van Dyck. 



New Brunswick, N.J., July 30. 



BOOK-REVIEWS. 



The History of Human Marriage. By Edward Westermaeck. 

 New York, Macmillan. 8°. $4. 



This is one of the most elaborate works on the history of social 

 institutions that we have met with. The author is lecturer on 

 sociology in the University of Fmland at Helsingfors, yet his book 

 was written by himself in English, which is to him a foreign lan- 

 guage. He modestly tells us in his preface that, as originally 

 written, the book contained some un-English expressions, which 

 were corrected by his English friends ; but the ease and clearness 

 of the style show that he is a master of the art of expression, and 

 make his work far more interesting than works on such subjects 

 are apt to be. The word " human" in the title of the book is 

 tautological ; for there is no marriage known to us except the 

 human, and Mr. Westermaick's attempt to show that the mat- 

 ing of animals is the same thing as marriage is by no means 

 successful. Marriage is a moral institution, and therefore cannot 

 exist except among moral beings ; and Mr. Westermarck's failure 

 to duly appreciate the moral aspects of his subject is the principal 

 defect of his work. 



As a descriptive history of marriage, however, in the many 

 forms it has assumed, the work could hardly, in the present state 

 of our knowledge, be surpassed. It opens with a discussion of the 

 proper method to be pursued in this and similar inquiries, as to 

 which the author is more prudent than some writers have been. 

 He remarks that ' ' nothing has been more fatal to the science of 

 society than the habit of inferring without sufficient reasons from 

 the prevalence of a custom or institution among some savage peo- 

 ples that this custom, this institution, is a relic of a stage of de- 

 velopment that the whole human race once went through " (p. 2). 

 It was high time to sound this note of caution, and we trust that 

 other inquirers into early history will give heed to it. Having 

 settled on his method of investigation, Mr. Westermarck goes on 

 to present the different phases of his subject, such as the antiquity 

 of marriage, the hypothesis of promiscuity among primitive peo- 

 ples, the influence of affection and sympathy, the forms of mar- 

 riage, the ceremonies attending it, and many other matters per- 

 taining to the marriage relation. He shows a very wide as well 



as intimate knowledge of the facts, so far as they have been dis- 

 covered, and both his facts and his arguments will have to be 

 considered by all who may write on the subject hereafter. 



His opinions on certain fundamental points are at variance with 

 those of most previous writers, and hence his work is likely to 

 give rise to some controversy. He rejects the hypothesis that 

 promiscuous intercourse was once everywhere prevalent, and his 

 arguments on this point deserve careful attention. In some of 

 his other theories he does not seem to us quite so fortunate- For 

 instance, he maintains that there was in the eai'liest times a human 

 pairing season similar to that of animals, the sexual passion being 

 dormant the rest of the year; yet he brings no adequate evidence 

 to support this view, and hardly any evidence at all. Again, in 

 speaking of the prohibition of marriage among near kindred, he 

 remarks that savages could hardly have known that such mar- 

 riages are physically injurious to the race, and so he attempts to 

 account for the prohibition by the principle of " natural selection." 

 He thinks that " there was no doubt a time when blood relation- 

 ship was no bar to sexual intercourse. But variations, here as 

 well 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 " 

 (p. 353). But what we want to know is why some of our ances- 

 tors avoided such breeding while others did not; and it is no an- 

 swer to this question to tell us that, after the two customs had 

 been established, the one prevailed over the other. But whatever 

 may be thought of some of Mr. Westermark's theories, his work 

 will be indispensable to all students of the early history of man- 

 kind. 



Justice. By Herbert Spencer. New York, Appleton. 12°. 

 $.25. 



This is intended to form the fourth part of Mr. Spencer's " Prin- 

 ciples of Ethics," of which only the first part had previously ap- 

 peared. Only the earlier chapters of the book deal with the gen- 

 eral principles of justice, the bulk of it being devoted to their 

 application. We cannot say that in our opinion the work is a 

 success, the author's fundamental ideas being vague and inconsis- 

 tent. His attempt to show that there is such a thing as " animal 

 ethics " is hardly worth discussing ; but when he comes to treat 

 of human justice he lays down as its fundamental principle a 

 proposition which will meet with little acceptance from philoso- 

 phers. He maintains that "each individual ought to receive the 

 benefits and the evils of his own nature and consequent conduct ; 

 neither being prevented from having whatever good his actions 

 normally bring to him, nor allowed to shoulder off on to other 

 persons whatever ill is brought to him by his actions" (p. 17). 

 Now according to this rule, if a man in consequence of his own 

 mistake meets with an accident that disables him, it is just for 

 other men to leave him to perish ; but most people would say it 

 was unjust. 



Mr. Spencer afterward modifies this principle somewhat by 

 the provision that no man shall interfere with the freedom of 

 others; and thus he reaches what he calls "the formula of jus- 

 tice," which is as foUows: "Every man is free to do that which 

 he wills, provided he infringes not the equal freedom of any other 

 man" (p. 46). This is a familiar principle of the common law; 

 and it is rather surprising to see it presented in this work as if it 

 was something novel. It is by no means sufficient, however, as a 

 universal rule of justice, as Mr. Spencer himself finds when he 

 comes to deal with the rights of children; for if children were 

 left to themselves merely, without help or interference from older 

 persons, they would die. Accordingly Mr. Spencer falls back 

 upon another principle, namely, the necessity of preserving the 

 species, which makes it the duty of the parents to support and 

 protect their offspring. Thus he lays down two quite distinct 

 principles of justice, and he nowhere takes the trouble to reduce 

 them to one nor to show how they are to be reconciled with each 

 other. He fails, too, as all the associationists have failed, to 

 account for moral obligation. Why should I refrain from in- 

 fringing the freedom of others if it happen to be for my advan- 

 tage to infringe it ? and why am I bound to preserve the species ? 

 Mr. Spencer scarcely touches this question in the body of his 



