THE PINEAL BODY 215 



cerebral and hypophyso-cerebral ratio bear out this observa- 

 tion and definitely indicate an increase in the proportion between 

 the brain and the epiphysis from the first year of life to the 

 fifth epoch, between sixty and seventy years. If compared with 

 the conditions observed in a definitely known endocrinic organ, 

 the hypophysis, it will be observed that in the first period the 

 weight ci the pineal bcdy is 30 per cent of the hypophysis; in 

 the second epoch it is also 30 per cent; in the third epoch it is 

 35 per cent, an increase which is of much importance and inter- 

 est in this connection, since it is the general supposition that the 

 gland has its greatest functional activity during this time of 

 life. - In the fourth epoch the epiphysis is 22 per cent of the hypo- 

 physeal weight, while in the fifth epoch it is 25 per cent. 



It should be borne in mind, while considering these figures, 

 that the hypophysis is a compound organ, being made up of a 

 neural portion in addition to an element derived from the oral 

 ectoderm. Its greater weight, therefore, is in part, at least, 

 explained by its non-glandular neural portion, and its total 

 glandular weight would be represented by a fraction only of this 

 total. In this light, the proportion between the epiphysis and 

 the hypophysis would be materially changed, and while it is 

 impossible to say exactly what ratio the neural portion of the 

 hypophysis bears to the glandular portion, it would be safe to 

 assume that the proportion is as 1 : 2. 



' From this standpoint, the figures concerning the epiphysis 

 assume more definite significance and would seem to point 

 strongly to the supposition that an organ destined to become 

 regressive would scarcely keep pace so constantly in its weight 

 increment with an organ like the hypophysis of known endo- 

 crinic function. The figures cited are suggestive in another 

 sense, namely, they would seem to show that the activity of the 

 pineal organ, should such be accredited to it, does not cease at 

 any particular period of life, and that while there may be reason 

 to believe that the greatest functional activity is present in the 

 third epoch, between the third and fifteenth years, there are 

 good reasons to believe that the organ does not cease to perform 

 its functions even up to the time of old age. 



