CHEMICAL ACTIONS: PROTOPLASM 



Then the latter prevails, and only the harmful 

 consequences become visible. 



The discovery of further interesting chemical 

 stimuli was made in the course of the studies of the 

 consequences of extirpation of certain organs, as 

 the thyroid gland or the suprarenal bodies in 

 animals. This procedure invariably causes fatal 

 consequences for the organism. It is followed by 

 serious disturbances of the normal metabolism and 

 finally by death, so that there is no doubt that 

 these glands perform important functions. But 

 since the organs mentioned have no excretory duct, 

 the substances produced by them must be trans- 

 ferred directly into the circulation of the blood. 

 This internal secretion appears to be of the 

 greatest importance. Seemingly very different 

 substances are produced by these glands, not only 

 proteids, but also aromatic carbon compounds 

 have been stated to play a part in internal secre- 

 tion. But all these substances exert stimulating 

 and regulating effects on the organism. They are 

 generally united under the name of Hormones. 

 Even plants seem regularly to produce such 

 substances. The swelling of the ovary after 

 pollination is caused by certain soluble substances 

 of the pollen. Very likely the formation of flowers, 

 or of the sexual organs in lower plants, is con- 

 nected with the occurrence of Hormones in the 

 organism of plants. 



Most remarkable chemical actions and counter- 



127 



