746 



RKPORT — 1884. 



Section D.-BIOLOGY. 



rREsiDENT OF Tni; Sectiox — rrofessor ir. N. M()sEr,EY, M.A., LL.D., F.R.S., 



F.L.S., F.U.G.S., I'.Z.S. 



■Militivi.lj'f 



THUnSDAY, AUGUST 28. 



The PresidiuNT delivered the foUowiiii: Address : — 



In appointing: the phononieim of pelagic and deep-sen life as one of the .siiLjects 

 specially seleeted fur eonsideration at tiie present nieetinp of this Section, the 

 Organising Coniniittft^ have, I think, done wisely. Our knowledge of the siiljject 

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

 the pliysiologist as Avell as the zoologist, and in some features claims a share of atten- 

 tion from tlie hotanist. And the proximity here of the United States, to wiiidi 

 science is indebted for so many imjiortant discoveries on deep-sea matters, isastiMiig 

 argument in lavour of the subject being brought forward at a British Associatiou 

 meeting on this side of the Atlantic. 1 have naturally been led to choose tlic con- 

 sideration of some deep-sea biological (questions as the Mubject of my address by tli. 

 special interest wliich I have been led to take in deep-sea phenomena generallv, 

 owing to my long participation in actual deep-sea research during the vovage nf 

 H.M.S. 'Challenger.' 



Unfortunately, the physiology of the deep-sea life lias until lately received liut 

 little attention from profe,''.sed physioloi.nsts. No phy.siologi.st has, as far as J am 

 aware, as yet .set forth comprehensively and dwelt upon t he numerous diiUcuhit,- 

 wliich are encountered when the attempt is made to understand the mode in whiil. 

 the ordinary phy.siological processes of vertebrata and other animals are carried mi 

 un<ler the ])eculiar physical conditions which exist at great depths. 



Whilst I was on the ' Challenger 'voyage, absorbed principally in the zooloj.'ica! 

 discoveries daily resulting from the dredging operations, 1 received a letter from 

 my revered teacher, Prole.s.sor Ludwig, of Leipzig, which brought deep-sea plieiio- 

 mena before me in a very different light. The Profes.sor naturally regarded dtrp- 

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

 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, u- 

 to the amount of o.^ygen 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 

 Dittmar, on ' liesearche.'^ into the Composition of the Ocean-Water collected V 

 II.M.S. " Challenger," ' which has appeared during the j^resent year, and wliieli 

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

 to what w^as before suspected, the presence of free carbonic acid in sea-water i- 

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

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

 acid increases when the temperature falls, and vice versa. Deep-sea water does n"t 

 contain an abnormal proportion of loose or free carbonic acid. 



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



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

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



dJ. 



