2 NATURAL SCIENCE. July. 



In Dr. Haacke's " Gestaltung und Vererbung," a notice of which 

 appears in another part of our columns, almost a burlesque of this 

 tendency to mathematical reasoning appears. Again and again 

 consecutive pages are filled with formulae that stretch over three lines 

 of serried signs and figures and brackets, while his new theory of 

 heredity and development depends upon geometrical conceptions. 



These physical views are to be traced chiefly in the work of 

 morphologists, and more than once contributors to our columns have 

 contrasted, in this respect, morphological work with the tendency 

 towards vitalism of the physiological school of the present time. But 

 the contrast is more apparent than real. The " vitalists " are 

 studying the phenomena of life as things-in-themselves, as being 

 kindred to, but not compounded of, chemical and physical phenomena. 

 The result of physical reasoning applied by morphologists as yet 

 has been to give a fuller idea of the individual and homogeneous 

 nature of living matter all through the animal and plant kingdoms, 

 rather than to explain the nature of living matter on physical principles. 

 The new method tends not to make biology a branch of geometry, 

 but to introduce a new science of biometry. 



Another Critic of Weismann and Another Theory. 

 In addition to Dr. Haacke's book, we have before us two 

 pamphlets published at Hamburg in 1894, but originally delivered as 

 addresses, by Dr. George Pfeffer, to the Naturwissenschaftlicher 

 Verein. The title of the first, rendered into English, is " The 

 Intrinsic Errors of Weismann's Germ-Plasm Theory." It objects 

 to the theory chiefly on the ground that it implies the conception that 

 Natural Selection works in the same method as would be employed 

 by a creator working with a definite object in view. It is certainly 

 the case that many organisms have structures or properties by which 

 they are saved from destruction or gain an advantage in the struggle 

 for existence. Dr. Pfeffer thinks, and, it is true, many critics of 

 Weismann agree, that Weismann's view of evolution implies an 

 illogical extension of the above statement into the statement that 

 these adaptations, protective or aggressive, have been called into 

 existence by Natural Selection because of their utility; that, in fact. 

 Natural Selection, on Weismann's showing, is a teleological cause. 

 Of course, Weismann himself has expended much pains in attempting 

 to convince, and has succeeded in convincing many, that his theory 

 impHes no such illogicality. We do not think that Dr. Pfeffer has 

 brought forth anything that will increase the faith of the opponents of 

 AVeismann or unsettle that of his supporters. The title of the other 

 pamphlet is more difficult to render into English. As near as may 

 be it is " The Transformation of Species — a Process of Self-Develop- 

 ment." It is based on addresses delivered in March, 1893, ^^^ i" 

 January, 1894. Like Dr. Haacke, he makes much of the " blessed 

 word " equilibrium. The whole organic world is in equilibrium; a 



