January 15, 1897.] 



SCIENCE. 



109 



various vertebrates, explanation of tlie prema- 

 ture birth of the opossum, the main outlines of 

 the history of the mammary glands and pla- 

 centa and a number of other items. 



It was published and appeared as a separate 

 work, because it was felt that the facts described 

 were suflBciently novel and important to war- 

 rant such a course, and not merely ' to secure 

 attention ' to my theory. The ' note of per- 

 sonal exultation ' is no such theory; it is in- 

 tended to be an invitation aud challenge to 

 scientific men to examine and, if possible, to 

 refute my arguments. The latter is something 

 the reviewer has carefully avoided to attempt. 



The last paragraph cited (5) is merely the 

 expression of the critic's personal opinion and, 

 unless supported by argument, can carry no 

 conviction. The reviewer offers no reasons for 

 his adverse judgment; until he does so, it is out 

 of question to consider, or even to understand, 

 what standpoint he takes up. A mere denial 

 of the truth of my theory is not argument, but 

 dogmatism. J. Beard. 



University of Edinburgh. 



Mr. Beard's paper on the transient nervous 

 system was well known to me, and I consider 

 my statements correct, aud I made them de- 

 liberately. There are two methods, and only 

 two, that enable the investigator to trace the 

 forms and connections of nerve-cells, the Golgi 

 method and the methylen-blue method. Mr. 

 Beard employed neither of these, and, as a 

 matter of fact, has not traced, and was neces- 

 sarily unable to follow, all the essential trans- 

 formations of these cells. His research is an 

 extremely interesting one, and, in my opinion, 

 important, but the results are not available in 

 support of the ' Phorozoon ' theory. The num- 

 ber of embryos and of years devoted to the re- 

 search do not make up for the exclusive use of 

 an insuflicient method. 



The facts referring to the condition of the 

 organs at the ' critical stage ' are given more or 

 less fully in all embryological text-books. The 

 occurrence of the critical stage is not specially 

 mentioned, because no embryologist, except 

 Beard, has heretofore regarded it as more or 

 less important than preceding and subsequent 

 stages. The error of Mr. Beard's, which I 



note, is the assumption that this stage is 

 ' critical,' for stages before it and after it could 

 equally well be selected and traced through the 

 vertebrate series as accurately as the ' critical ' 

 stage. If Mr. Beard knows the contrary of 

 this he must have compiled the characters of 

 various classes of vertebrates at other stages 

 and found that they do not agree. The de- 

 tailed publication of such a compilation must 

 precede a claim for serious attention to his 

 hypothesis. As stated in the notice of Beard's 

 work, the compilation of characteristics in ver- 

 tebrate embryos of various classes and all ap- 

 proximately at the same stage is useful, and if 

 corresponding tables of other stages were also 

 compiled they would also be useful. It would 

 be interesting to know what proof establishes 

 the ' critical ' nature of the stage selected by 

 Mr. Beard. He has not as yet published any 

 such proof, although the onus probandi is his. 

 He calls for disproof, but proof from him must 

 come first. Mr. Beard states that he compiled 

 the facts, yet complains that I say the facts are 

 well known. Does he mean that the facts he 

 quotes from various authors were unknown? 

 My review is a protest against two tendencies: 

 first, to solve, embryologically, morphological 

 problems without suflicient regard to histogen- 

 esis; second, to push speculation indefinitely 

 beyond observation. Both tendencies have 

 been marked in Mr. Beard's previous papers, as 

 well as in the one under discussion. 



I regret that my criticism cannot be more 

 favorable. Chaeles S. Minot. 



SCIENTIFIC LITERATURE. 



Tlie Survival of the Unlike. A collection of Evolu- 

 tion Essays suggested by the study of domes- 

 tic plants. By L. H. Bailey. New York, 

 The Macmillan Company. 1896. 515 pp. 

 8vo. 



Whatever Professor Bailey writes is interest- 

 ing reading. He has the rare gift of an enter- 

 taining style, and what he writes people want 

 to read. All his previous books have been 

 widely read, and this will prove to be no ex- 

 ception to the well-established rule. The se- 

 cret of this popularity, if there be any secret 

 about it, is that when he writes he has some- 



