310 



Dr. W. M. Bayliss and Prof. E. H. Starling. [Mar. 21, 



flame. Special directions were given to the glass blower about this, 

 because the effect of it would be the production of considerable tension 

 in that part of the glass. Notwithstanding my directions, some of 

 the tubes were rounded off in the lamp and the effect was as I had 

 foreseen. The only one of these ends which I used burst. In the 

 case of ends which have been cut off and not heated, the fracture is 

 confined to the part of the tube outside the apparatus. In the case of 

 the end with rounded edges the outside part was fractured in the 

 ordinary way, and in addition the rounded portion, which was 

 exposed to no difference of pressure, exploded out of sympathy, much 

 after the fashion of a Prince Rupert's drop. 



I am continuing this investigation, and I hope shortly to be in a 

 position to be able to communicate further results to the Society. 



Ckoonian Lectuee. — " The Chemical Regulation of the Secretory 

 Process." By W. M. Bayliss, F.R.S., and E. H. Stabling, 

 E.R.S. Received March 21 —Read March 24, 1904. 



In the complex reactions which make up the life of an individual, 

 and the evolution of which has been the determining factor in the 

 individual's existence, we may distinguish two main types; though, 

 as in all attempts at classification of biological processes, the line of 

 division between the two types must be more or less indistinct. 



In the first place we have those reactions which depend for their 

 production on some special structural arrangement, and are therefore 

 determinant factors in the evolution of form. In some cases the 

 adaptive production of organs or protective mechanisms may be 

 associated with a direct chemical reaction, as in the formation of 

 protective tissues. In most cases, in higher animals at any rate, 

 such an adaptation will be intimately associated with the development 

 of the central nervous system, of which the peripheral parts of the 

 body must be regarded as the executive mechanisms. In general, 

 however, we may say that this type of adaptation is dependent on the 

 adaptive growth of cells. 



The second type, the more primitive of the two, involves, in the 

 first place, not so much a change in the growth or arrangement of 

 cells, as a change in the metabolism of pre-formed cells or struc- 

 tures. It may, perhaps, be looked upon as a preliminary to the first 

 type, namely, structural change. It is, however, of special interest, 

 since its mechanism is subject to analysis by physiological methods. 

 Instances of chemical adaptation may again be divided into two 

 groups. In the first place we have the chemical adaptation to the 



