370 



SCIENCE. 



[N. S. Vol. XX. No. 507. 



Liisebrink on one side and Duval, van 

 Beneden and myself on the other, of which 

 debates the object was to make out in how 

 far the material of the proliferating pla- 

 ' eenta should be looked upon as maternal 

 and in how far as embryonic, trophoblastic 

 tissue. 



These debates will no doubt, in the course 

 of time, as the number of carefully ob- 

 served cases increases, lead to a unanimous 

 interpretation. As it was, I have myself, 

 for sheer diiBdenee of attributing too prom- 

 inent a part to trophoblastic proliferation 

 (of which I was, nevertheless, together with 

 Duval, the first advocate), in one case 

 stopped short of the real solution, and have 

 for the hedgehog restricted the extent of 

 the trophoblast more than was necessary. 

 Since then I have corrected this in a doctor 

 dissertation of one of my pupils (Resink, 

 1903), but there is no doubt that I am 

 myself thus responsible for a certain 

 amount of vagueness and misrepresenta- 

 tion which has prevailed in the application 

 of the term trophoblast to different pla- 

 centas, more particularly of man and the 

 monkeys, where the question arose in how 

 far certain syncytial tissues should be 

 looked upon as maternal or as embryonic. 

 Even for pathological anatomy this proved 

 to be a momentous question in so far as the 

 decidubma malignum, if traced to remains 

 of trophoblast cells, would be very different 

 from other deciduomse, that found their 

 origin in maternal tissue. 



Now that the placentation of Tarsius, 

 Ihipaja, Sorex, Vespertilio, Cercocebits, 

 Talpa, Galeopithecus, Sciurus, Lepus, a. o., 

 has been more carefully examined (tropho- 

 blastic proliferation having been figured 

 by Selenka as early as 1887, for one of the 

 Didelphia [Opossum] ), divergence of opin- 

 ion will in a few years hence have been 

 replaced by unanimity also on this head. 



And then the application of the name 

 trophoblast to those placental elements that 



arise from the embryonic layer originally 

 designated by that name will be in no way 

 confusing, but will, on the contrary, con- 

 tribute to keep before our eyes the intimate 

 relation between the facts as they take 

 place under our eyes and their phylogenetic 

 origin. 



With perfect justification Strahl has pro- 

 tested (Hertwig's 'Handbuch der Ent- 

 wickelungslehre der "VVirbelthiere, ' I., 2, p. 

 311) against a misapplication of the term- 

 inology, which I have attempted once more 

 to explain in this article, when authors who 

 have insufficiently studied the subject even 

 go so far as to speak of a matervMl tropho- 

 blast beside the embryonic! 



I hope that this paper may henceforth 

 render misinterpretations such as are dis- 

 cussed in it impossible. 



A. A. W. HUBRECHT. 

 University of Utrecht. 



SCIENTIFIC BOOKS. 



Geographic Inflitences in American History. 



By Albert Perry Brigham, Professor of 



Geology in Colgate University. Boston, 



Ginn & Co. 1903. Pp. 365. 



Professor Albert Perry Brigham, of Col- 

 gate University, has made a notable contribu- 

 tion to American geographical literature in 

 his book, ' Geogi-aphie Influences in American 

 History,' published by Ginn and Co. The 

 divisions of the book are mainly physiographic, 

 but the author has not allowed this subject 

 undue prominence. 



Chapter one is entitled ' The Eastern Gate- 

 way of the United States.' The central idea 

 is the development and importance of the 

 Hudson-Mohawk valley — its physiographic or- 

 igin and its influence upon American history. 

 Its importance in the Revolution and the war 

 of 1812, and the successive waves of immi- 

 gration which passed through it and left 

 their record in the ' successive layers of geo- 

 graphic names ' are well brought out. The in- 

 terdependence • of the valley and the cities 

 which have grown up along it and the condi- 

 tions of growth of the metropolis at its mouth 

 are discussed. 



