746 kepobt — 1884. 



Section D.— BIOLOGY. 



President of the Section — Professor H. N. Moseley, M.A., LL.B., F.R.S., 



F.L.S., F.R.G.S., F.Z.S. 



THURSDAY, AUGUST 28. 

 The President delivered the following Address : — 



In appointing; the phenomena of pelagic and deep-sea life as one of the subjects 

 specially selected for consideration at the present meeting of this Section, the 

 Organising Committee have, I think, done wisely. Our knowledge of the subject 

 is at present in most active progress. It is one of the widest and deepest interest to 

 the physiologist as well as the zoologist, and in some features claims a share of atten- 

 tion from the botanist. And the proximity here of the United States, to which 

 science is indebted for so many important discoveries on deep-sea matters, is a strong 

 argument in favour of the subject being brought forward at a British Association 

 meeting on this side of the Atlantic. I have naturally been led to choose the con- 

 sideration of some deep-sea biological questions as the subject of my address by the 

 special interest which I have been led to take in deep-sea phenomena generally, 

 owing to my long participation in actual deep-sea research during the voyage of 

 H.M.S. < Challenger.' 



Unfortunately, the physiology of the deep-sea life has until lately received but 

 little attention from professed physiologists. No physiologist has, as far as I am 

 aware, as yet set forth comprehensively and dwelt upon the numerous difficulties 

 which are encountered when the attempt is made to understand the mode in which 

 the ordinary physiological processes of vertebrata and other animals are carried on 

 under the peculiar physical conditions which exist at great depths. 



Whilst I was on the ' Challenger ' voyage, absorbed principally in the zoological 

 discoveries daily resulting from the dredging operations, I received a letter from 

 my revered teacher, Professor Ludwig, of Leipzig, which brought deep-sea pheno- 

 mena before me in a very different light. The Professor naturally regarded deep- 

 sea questions mainly from a physiological point of view, and asked a series of most 

 suggestive questions bearing on it. I am much indebted to him for this and recent 

 letters on the same subject. One of the first questions he asked was, naturally, as 

 to the amount of oxygen present in deep-sea water. A knowledge of the con- 

 ditions under which gases occur in a state of absorption in the ocean-waters is of 

 primary importance to the physiologist. With regard to this subject most valuable 

 information is contained in the report by the distinguished chemist, Professor 

 Bittmar, on ' Researches into the Composition of the Ocean-Water collected by 

 H.M.S. " Challenger," ' which has appeared during the present year, and which 

 embody Mr. J. Y. Buchanan's results. 1 It appears from his results that, contrary 

 to what was before suspected, the preserice of free carbonic acid in sea-water is 

 an exception. What carbonic acid is present occurs as a bicarbonate, in general 

 more or less incompletely saturated. In surface-waters the proportion of carbonic 

 acid increases when the temperature falls, and vice versa. Beep-sea water does not 

 contain an abnormal proportion of loose or free carbonic acid. 



Hence, with regard to Mr. John Murray's interesting discovery that after 



1 'Official Report on the Scientific Results of the Voyage of H.M.S. " Challen- 

 ger," ' Physics and Chemistry, vol. i. 



