president's address. 23 



the actual grinding to powder of these already very minute bodies— first 

 established this, and now successive discoveries of intraceUular 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 tlic chemical point of view) becomes a chain 

 of ferment actions. Another most significant advance in animal physio- 

 logy has been the sequel (as it were) of Bernard's discovery of the 

 formation of glycogen in the livei-, a substance not to be excreted, Ijut to 

 be taken up by the blood and lymph, and in many ways more important 

 than the more obvious formation of bile wliich 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 suprarenals, 

 thyroid, and others, secrete indispensable products into the blood and 

 lymph. Hence myxoedema, exophthalmic goitre, Addison's disease, and 

 other disorders have been traced to a deficiency or excess of internal 

 secretions from glands formerly regarded as interesting but unimportant 

 vestigial structures. From these glands liave in consequence been ex- 

 tracted remarkable 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 : the thyroid yields a substance which influences the 

 growth of the skin, hair, bones, &c. ; tbe pituitary gland, an extract 

 which is a specific urinary stimulant. Quite lately the mammalian ovary 

 has been shown by Starling to yield a secretion which influences the state 

 of nutrition of the uterus and manimse. Had I time, I might .say a great 

 deal more on topics such as these — topics of almost infinite importance ; 

 but the fact is that the mere enumeration of the most important lines of 

 progress in any one science would occupy us for hours. 



Nerve-physiology has made immensely important advances. There is 

 now good evidence that all excitation of one group of nerve-centres is 

 accompanied by the conctirrent inhibition of a whole series of groups of 

 other centres, whose activity might interfere with that of the group 

 excited to action. In a simple reflex flexure of the knee the motor- 

 neurones to the flexor muscles are excited, but concurrently the motor- 

 neurones to the extensor muscles are thrown into a state of inhibition, 

 and so equally with all the varied excitations of the nervous system 

 controlling the movements and activities of the entire body. 



The discovery of the continuity of the protoplasm through the walls 

 of the vegetable cell by means of connecting canals and threads is one of 

 the most startling facts discovered in connection with plant-structure, 

 since it was held twenty years ago that a fundamental distinction between 

 animal and vegetable structure consisted in the boxing-up or encasement 

 of each vegetable cell-unit in a case of cellulose, whereas animal cells were 

 not so imprisoned, but freely communicated with one another. It perhaps 

 j.s on this account the less surprising tliat lately something like sen.se- 



