296 PROGRESS OF SCIENCE IN THE CENTURY. 



As has been noticed in the preceding section, the 

 discovery of internal secretions, like those of the 

 thyroid and the pancreas, shows that various organs 

 of the body act on the blood passing through them in 

 some specific way which is essential to the health of 

 the whole. Even at the beginning of the century 

 (1801) Legallois had a prevision of this; in 1857 it 

 was brought into prominence by Claude Bernard's 

 discovery of the glycogenic function of the liver ; in 

 1889 it was re-emphasised when von Mering and 

 Minkowski showed that the pancreas, besides being 

 a digestive gland, acted as a regulator of the quan- 

 tity of sugar produced or destroyed in the organism. 



When the reproductive organs come to maturity, 

 changes ensue in many parts of the body which bear 

 witness to an intimate correlation, though we are 

 unable to follow the physiological links. The larnyx, 

 the hair, the milk-glands, and many other structures 

 feel the influence. Conversely, the removal of the 

 reproductive organs is followed by changes wide- 

 spread throughout the body — penetrating even into 

 the bones. Observations on the correlation between 

 the reproductive organs and the antlers of stags 

 (Rorig) are now so well-established, that one who 

 has given attention to the matter could predict from 

 a peculiarity of the antlers the state of the male 

 organs, or could argue from the appearance of ant- 

 lers in a female as to the abnormality of the ovaries. 



To sum up, there appears to he a noteworthy step 

 of progress in the discovery of intimate correlations 

 previously unsuspected, and in the (ijicipient) inves- 

 tigation of the manner in which these are brought 

 about. It implies a deeper realisation of the unity 

 of the organism. 



(4) Progress of Comparative Physiology. — As 



