170 THE STRUCTUKE OF MAN 



in the frequency of its occurrence in advanced age, as will be 

 seen from the following table : 



From the 1st 10th year occlusion observed in 4 per cent. 



10th 20th ,,H 



20th 30th ,,17 



30th 40th 25 



40th 50th 

 50th 60th 

 60th 70th 

 70th 80th 



27 



30 

 53 



58 



It follows from the foregoing table that in more than 50 per 

 cent of people over sixty years of age there is degeneration of the 

 vermiform process. In new-born children, on the other hand, 

 this phenomenon has never been observed, and the youngest 

 child in whom it has been found commencing was five years old. 

 Total occlusion is also similarly connected with age, though not 

 in nearly so marked a manner as partial closure. It has never 

 been observed before the thirtieth year ; and while it was not 

 found once in individuals between fifty and sixty, it was most 

 frequent in those whose ages ranged from sixty to seventy. Among 

 these, nine out of the twenty-one cases recorded showed complete 

 occlusion ; and since besides them there were seven just on the 

 point of closure, we may conclude that more than 50 per cent 

 were thus affected. 



A relation has further been proved to exist between the 

 length of the appendix and its degeneration. The longest 

 appendices (21 to 15 cm. long) kept their lumen throughout; 

 in those 14 and 13 cm. long, commencing obliteration of the 

 lumen was observed in four cases, and in those 12 and 11 cm. 

 long it was not found. From this point, however, occlusion 

 again increased as the length decreased. If we leave out of 

 account individuals under five years of age, in whom occlusion' 

 has not been observed, we find that it occurs as under, viz. 



Where the length of the appendix is 20 cm. in 34 per cent. 



9 18 

 32 



7 



40 

 30 

 70 

 66 



3 . 100 



Although this connection between length and frequency of 

 occlusion is, as the table shows, somewhat irregular, we may at 



