THE ADVANCE OF SCIENCE 115 



Great progress in the knowledge of the chemistry of 

 the living cells or protoplasm of both plants and animals 

 has been made by the discovery of the fact that ferments 

 or enzymes are not only secreted externally by cells, 

 but exist active and preformed inside cells. Biichner's 

 final conquest of the secret of the yeast-cell by heroic 

 mechanical methods the actual grinding to powder of 

 these already very minute bodies first established this, 

 and now successive discoveries of intracellular ferments 

 have led to the conclusion that it is probable that the 

 cell respires by means of a respiratory 'oxydase,' builds 

 up new compounds and destroys existing ones, contracts 

 and accomplishes its own internal life by ferments. Life 

 thus (from the chemical point of view) becomes a chain 

 of ferment actions. Another most significant advance in 

 animal physiology has been the sequel (as it were) of 

 Bernard's discovery of the formation of glycogen in the 

 liver, a substance not to be excreted, but to be taken 

 up by the blood and lymph, and in many ways more 

 important than the more obvious formation of bile which 

 is thrown out of the gland into the alimentary canal. 

 It has been discovered that many glands, such as the 

 kidney and pancreas and the ductless glands, the supra- 

 renals, thyroid, and others, secrete indispensable pro- 

 ducts into the blood and lymph. Hence myxcedema, 

 exophthalmic goitre, Addison's disease, and other dis- 

 orders have been traced to a deficiency or excess of 

 internal secretions from glands formerly regarded as in- 

 teresting but unimportant vestigial structures. From 

 these glands have in consequence been extracted re- 

 markable substances on which their peculiar activity 

 depends. From the suprarenals a substance has been 

 extracted which causes activity of all those structures 

 which the sympathetic nerve-system can excite to action : 



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