APPENDIX 0. 



DETERMINATION OF THE AGE OF SKULLS. 



[ Abridged from Broca'a Instructions*.] 



There are to be distinguished the following periods: First period of childhood, second period 

 of childhood, adult age, ripe age, senility. These indications are enough and are worth more 

 than those of years of age because the anatomical and physiological phenomena which they dem- 

 onstrate are more or less precocious according to individuals or according to race. In our race 

 these periods correspond nearly to the following ages: 



First period of childhood, from birth to the end of the sixth year: 



Second period of childhood 7 to 14 years. 



Youth 14 to 25 years. 



Adult age 25 to 40 years. 



Ripe age .> 40 to 60 years. 



Senility beyond 60 years. 



We give these figures as a concession to custom and to make the succession of the periods 



more easily appreciated. But let us hasten to add that they are for the most part very uncertain. 



* * * 



First period of childhood. From birth to the eruption of the first great molars, called sixth 

 year's teeth. * * * 



Second period of childhood. It commences at about the age of six years with the eruption of 

 the first permanent molar, which marks the beginning of the second dentition; it ends about the 

 age of thirteen or fourteen years, when the eruption of the four second permanent molars is com- 

 pletely achieved. * * * 



Youth. It commences when the eruption of the four second permanent molars is completely 

 achieved that is to say, when the crowns of these teeth are altogether on a level with those of the 

 first molars; it is finished when on the one hand the wisdom teeth are come out, and when on the 

 other hand the basilar suture is completely closed. 



Adult age, ripe age, and senility. Onward from the end of the third period the distinction of 

 ages is much more doubtful. It is based upon the observation of two phenomena which are 

 gradual and very irregular in their chronology. * * * 



Physiologically one is generally contented to divide all the time, which passes from the end of 

 youth to death into two periods: The period of gradual change, called indifferently virility, adult 

 age, or ripe age, and the period of decadence, called senility. In craniology the first of these 

 periods should be divided in two ages: Adult age, comprised between the cud of youth and the 

 beginning of the ossification of the sutures, and the period of gradual change from then on to 

 senility. The craniological distinction between adult age and ripe age is generally easy since it 

 rests upon the anatomical observation of the study of the sutures. * * * 

 Senility of the skull is recognized by the following characters: 



First. The sutures are mostly in an advanced or complete state of ossification; some of them 

 at least are entirely effaced and may have left not even a vestige. The others, with the exception 

 of the squamous suture, which sometimes remains open until a very advanced age, are more or 

 less ossified. * * * 



.'Instructions craniologiques et craniometritiues par P. Broca, Paris, 1875, pp. 128 et seq. 



285 



