506 



SCIENCE 



[N. S. Vol. XXXI. No. 796 



upon the production of artificial oxidases; of 

 the nature and supposed functional impor- 

 tance of the catalases, etc. It would be 

 scarcely possible in fact to enumerate in a 

 brief notice aU of the important points which 

 are discussed and reviewed. The author has 

 laid his fellow biologists, who may be con- 

 cerned in understanding the nature of physi- 

 ological oxidations, under a debt of gratitude 

 for his able and exhaustive presentation of 

 this difScult subject. We can only wish that 

 with his own extensive first-hand knowledge 

 of the facts he had attempted to winnow 

 from the great mass of contradictory or di- 

 vergent observations those that to him might 

 seem to be entitled to at least provisional 

 acceptance at the present time. The reader 

 who is not a specialist in this line of work is 

 somewhat at a loss to appreciate how the bal- 

 ance of' evidence tends in regard to many of 

 the disputed points. 



"W. H. Howell 



The Evolution of Worlds. By Peecival 

 Lowell. Pp. xiii + 262; 12 plates and 56 

 text cuts. New York, The Macmillan Com- 

 pany. 1909. $2.50 net. 

 This work is written in the well-known at- 

 tractive style of the author. It is interesting 

 and will probably fascinate and charm many 

 readers of popular science. Its charm, how- 

 ever, lies in the literary skill of the author, 

 in the attractiveness with which the book is 

 manufactured, in the heavy paper, its clear 

 type and its beautiful illustrations. As a 

 work of art the book is charming and valu- 

 able; as an exposition of scientific facts and 

 theories it is exasperating. 



The theme of the book is the evolution of 

 the solar system, the process by which the 

 planets came into existence, the phases 

 through which the world has passed, and 

 through which it is destined to pass. Ever 

 since Laplace, in 1796, formulated and pub- 

 lished the nebular hypothesis, the subject of 

 the birth, growth and death of worlds has 

 aroused great interest and has attracted many 

 able investigators. For nearly one hundred 

 years the beautiful and simple theory of La- 



place was accepted in its entirety by scientific 

 writers. During the last quarter of a century, 

 however, much has been learned concerning 

 the present condition of the solar system, and 

 many facts have been developed which, while 

 establishing the broad underlying idea of 

 planetary evolution, can not be reconciled 

 with the simple Laplacian hypothesis. Sir 

 George Darwin accepted the main outlines of 

 the nebular hypothesis and accounted for the 

 discrepancies between theory and fact by the 

 agency of tidal friction. But there are limits 

 .to the potency of tidal friction and even in its 

 modified form the nebular hypothesis fails to 

 account in a satisfactory manner for all the 

 complicated details of the solar system. 



Within comparatively recent years Cham- 

 berlin and Moulton have advanced what is 

 called the " planetesimal " or " spiral " hy- 

 pothesis. It explains many of the difficulties 

 encountered by the Laplacian or nebular hy- 

 pothesis and is undoubtedly the most satisfac- 

 tory working theory yet advanced. Their first 

 papers were published as early as 1900, since 

 which date they have from time to time elabo- 

 rated and developed their theory. 



Now, Lowell's book, in its main features, is 

 an exposition of the " planetesimal" theory, 

 but an exposition with no reference to, or 

 mention of, the work of Chamberlin or Moul- 

 ton. It is like the play of Hamlet with Ham- 

 let left out. Neither Chamberlin's nor Moul- 

 ton's name appears in the index, nor, in a 

 careful reading of the book, do we find any 

 mention of them or of " planetesimal " or 

 " spiral " hypothesis. This is not so strange 

 as at first glance it might appear, for Pro- 

 fessor Lowell has recently attacked the sci- 

 entific value of the theory and the standing 

 of its authors. In the Atlantic Monthly for 

 August, 1909, Lowell refers, in a foot note, to 

 Chamberlin and the planetesimal theory in the 

 following words : " Astronomically he is una- 

 ware that what prompted his contention, the 

 planetesimal hypothesis, is mathematically un- 

 sound." The publication of the " Evolution of 

 Worlds," with its nameless presentation of the 

 planetesimal hypothesis, shows that while 

 Lowell appreciates the fundamental correct- 



