Miscellaneous. 371 



together representing an entire day of twenty-four hours. But 

 other observations by myself have given, as the average growth 

 of the hair of tiie head in persons who had been shaved, | of an 

 inch for the week, and consequently -J--^ of an inch for the twenty- 

 four hours. Now the length of hair comprehended by the white 

 and the brown in the present case is .^ of an inch, and con- 

 sequently a much more active growth than is normally met with — 

 corresponding, in fact, in a similar ratio, with thirty- seven hours 

 instead of twenty-four. 



I therefore refrain from speculating upon the cause of alternation 

 of the healthy and morbid structure presented by this case, and 

 restrict myself to the narration of the fact that during a certain 

 space of time, amounting to a day or more, tlie hair is produced of 

 normal structure, while during another space of time of undeter- 

 mined extent the hair is produced unhealthily, — that the periods 

 of healthy formation correspond pretty accurately in extent, as do 

 those of unhealthy formation, while the latter, in measurement, 

 are only half as extensive as the former, — moreover, that the differ- 

 ences of the pathological operation are, the production of a horny 

 plasma in the normal process, and of serous and watery cell-contents 

 in the abnormal process. 



I may further observe that it is by no means improbable that the 

 "dead" and faded hair which is met with after some illnesses and 

 in instances of debilitated health may be due to a similar pathological 

 process, although wanting in the periodicity and alternation which 

 render the present case so remarkable. 



MISCELLANEOUS. 



Theory of the Skull and the Skeleton. 



To the Editors of the Annals of Natural History. 



Gentlemen, — In your December Number Mr. Herbert Spencer 

 wrote claiming to have first enunciated the theory of growth dis- 

 cussed in my epitome-paper on the theory of the skeleton. At this 

 the earliest opportunity possible, I wish to say a word in explanation. 



I. I have never read any of Mr. Herbert Spencer's writings, nor 

 do I know any one who has read them. I was therefore quite un- 

 aware that my views would find a single supporter beyond the circle 

 of friends with whom they had been discussed. 



II. The theory of growth given in the 'Annals' for Nov. 1S6G 

 was first expounded, so far as I am concerned, in a paper entitled 

 "Researches on the Homologies of the Bivalve Mollusca," read be- 

 fore the Cambridge Philosojdiical Society, March 17, 18G2. The 

 same doctrine was again urged in a paper on the meaning and value 

 of some structures and modifications of Tctrabranchiate Shells, read 

 Nov. 10, 1862, a portion of which was printed in the 'Quarterly 

 Journal of Science' for Oct. 180-1. The same view is implied, 

 though not directly stated, in my paper on SaurospondyluSy printed in 

 the 'Annals' for Sept. 1865; and it is known to certain of my 

 friends that the paper '' A theory of the Skeleton" was written 



