Miscellaneous. 145 



In my judgment, this is only another and more emphatic way of 

 stating the coordination of structure and function which has been 

 insisted on by Prof. Owen and other naturalists again and again. In 

 the first passage that I have quoted all this dependence of structure 

 on "conditions" is assumed to be true. In the second passage, 

 assuming it to be true, it is generalized into a law. In the third 

 passage, assuming the existence of the law, its results are assumed 

 to be tolerably uniform. 



Now I am not aware that any number of assumptions, vague 

 ideas, or guesses will make a discovery ; and if they had done so, 

 are we not entitled to assume that the discoverer, instead of pub- 

 lishing it anonymously, in a few vague sentences at the end of a 

 review in a specially professional periodical, would have avowed his 

 great thought, and brought it prominently before naturalists who 

 could judge of its value ? especially as he is now anxious to have 

 credit for it. 



I have also had an opportunity of referring to the ' Principles of 

 Biology ;' and although Mr. Spencer insists with admirable clearness 

 on the correlation of structure and function, and, as in the review, 

 on the modification of structures by " incident forces," I did not 

 notice that these "incident forces" were defined; while, so far as I 

 could understand, Mr. Spencer confessed that he did not altogether 

 see how their results were produced. 



If this is a correct statement of Mr. Spencer's vague hypothesis, 

 I submit that, but for the terms " pressure and tension," and 

 " mechanical theory," our views have little in common. His appears 

 to me to have been an idea evolved out of an intellectual conscious- 

 ness of what ought to be. My view was arrived at inductively from 

 a long investigation ; and it was only when I was assured by mathe- 

 maticians, chemists, physicists, and others of their willingness to 

 cooperate in eventually demonstrating the view, that I consented to 

 publish a sketch of my method of studying the theory of the skele- 

 ton. For it is a part of a larger system referring the phenomena of 

 nature to their ultimate and actual physical causes, many of which 

 in their applications to life are discussed in a book of mine shortly 

 to be published, on " The Dynamical Geology of Great Britain." 



I am, Gentlemen, 



Very faithfully yours, 



Harry Seeley. 



Note on the Phenomena of Muscular Contraction in #Ae Vorticellae. 

 By C. RouGET. 



Living muscles can alternately shorten and elongate themselves : 

 this is their characteristic property. In purely elastic organs short- 

 ening only takes place after previous mechanical elongation ; the 

 muscles, on the contrary, can shorten themselves without appearing 

 to have undergone any extension. 



Whatever may be the causes of the elongation and shortening of 

 the muscular fibres, whether these opposite states result from a 



Ann. &; Mag. N. Hist. Ser. 3. Vol. xx. 10 



