Scientific Intelligence. — Anthropology. 195 



ent brains may vary. M. Magendie found that the brain in ad- 

 vanced age is specifically lighter by a fifteenth than in adults. 

 When we turn to physiological experiments, upon the uses of 

 parts in the brains of animals, we find that they afJbrd us no as- 

 sistance upon the question which we have been last considering ; 

 but at the same time, they present us results the most curious 

 and unexpected, and which perhaps the more deserve attention, 

 as their direct physiological interest is yet inferior to their value 

 in pathology. — Mayers Outlines of Human Physiology^ p. 298. 



16. Chi the Duration of Generations in tlie Eighteenth Cen- 

 tury. — Mr Villot, in a memoir lately read before the Academy 

 of Sciences of Paris, after mentioning that the duration of hu- 

 man generations was long confounded with the mean duration 

 of life, and that M. Fourier is the only person who has defined 

 the duration of generations in a clear and precise manner, shew- 

 ed, that, in this question, which is so interesting to natural his- 

 tory and chronology, there may be considered for both sexes, 

 the duration of generations of first-born parents, and the com- 

 mon duration of generations. The duration of the generation of 

 first-born persons presents no other interest than what relates to 

 the royal races, and the common duration of races is what it is 

 of importance to determine. He then shewed, that the only 

 practicable method of conducting this inquiry in a useful man- 

 ner, with reference to legal and authentic documents, is to have 

 recourse to the pubhc registers ; but that these registers having 

 been accurately kept only during the eighteenth century, it is on- 

 ly from that period that such inquiries can be made in France. 

 He then gave an account of the method which he employed in 

 determining the mean duration of generations in Paris in the 

 eighteenth century ; that is to say, in finding the mean value of 

 the interval of time between the birth of a father and the birth 

 of one of his sons, without regard to the order of their birth. 

 This method has the inconvenience of supposing but one genera- 

 tion for a family ; but this inconvenience disappears when the 

 question refers to a great number of families taken at random in 

 each of the parishes of Paris, and from all the registers of the 

 century. To determine the generation of a family, M. Villot 

 took from the registers the date of the birth of a male child, and 

 followed up the series of its parents to the commencement of the 



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