6-7 EDWARD VII. 



SESSIONAL PAPER No. 22a 



A. 1907 



XIII 



PROFESSOR MACALLUM ON THE CHEMISTRY OF MEDUSAE. 

 A CONDENSED RESUME OF RESULTS 



By Professor Edward E. Prince. * 

 Commissioner of Fisheries and Director of the Marine Biological Station of Canada. 



A detailed account of the laborious researches of Professor Macallum, F.R.S., on 

 the inorganic composition of certain marine jelly-fishes or medusae, appeared in the 

 Journal of Physiology, Vol. XXIY., pp. 213-241. These researches were commenced 

 in the summer of 1900, at the Marine Biological Station of Canada, and were con- 

 tinued during several seasons, with results so interesting in themselves and so sugh 

 gestive in their theoretical bearings as to justify repetition in an abbreviated popular 

 resume. The conclusions*which they appear to reasonably yield are, indeed, of such 

 profound biological significance that I have ventured to prepare a condensed summary, 

 divested as far as possible of technical phraseology. 



The medusae are amongst the most familiar of sea-side objects. These disc-shaped 

 Coelenterates, variously called jelly-fishes, sun-fishes and sea-nettles are, as Dallas 

 said, ' wonderfully beautiful creatures, though the amount of solid matter containeid 

 in their tissues is incredibly small. The greater part of their substance appears to 

 consist of a fluid differing little, if at all, from the sea-water in which the animal 

 swims, and when this is drained away, so extreme is the tenuity of the membranes 

 which contained it, that the dried residue of a jelly-fish, weighing two pounds, which 

 was examined by Professor Owen weighed only thirty grains.'* The fluid or so-called 

 jelly substance is, however, as Professor Macallum's researches show, not identical 

 with sea-water. Professor Macallum began his investigations by placing jelly-fishes in 

 vessels of sea water of various strengths, and by altering the proportions of individual 

 salts, he endeavoured to ascertain the action of the salts upon these living organisms. 

 As the exact composition of the jelly-fishes themselves was unknown, it soon appeared 

 to him that no conclusive results were possible until the composition of the medusae 

 had been ascertained. Two species, it may be mentioned, were specially studied, viz. : 

 Aurelia flavidula, Peron and LeSueur (closely allied to the European Aurelia aurita) 

 and Cyanea arctica, the first-named ranging from 5 to 10 inches in diameter, in the late 

 summer months when it is mature, while the last-named (Cyanea) may reach a size 

 of 3 to 5 feet across the disc, although smaller examples are most common. Specimens 

 of Cyanea arctica are on record having a diameter of not less than 74 feet, and possess- 

 ing tentacles over 120 feet long.f 



Owing to their simplicity of structure, especially their histological features, there 

 is a prevalent impression that jelly-fish imbibe, in sponge-like fashion, any fluids by 

 which they may be surrounded, and Professor Loeb, of Chicago, has published the 

 opinion that the existing chemical environment normally affects directly, not only the 

 chemical constitution of medusae; but their physiological activities as well, to a re- 

 markable extent. The swimming motions or pulsations of Aurelia and Oonionemus 

 are dependent, he declared, upon the presence of sodium, calcium, and potassium ions 

 in their sea-water environment. Professor Loeb instanced an experiment in which a 

 ring-like portion of the margin of Gonionemus was cut away, and the usual locomotor 

 pulsations ceased in ordinary sea-water; but, when placed in a | normal solution 



*Naturial History of the Aoiamiall Kingdom, London, G-riflin & Co., p. 70. 

 tRoiLleston's Forms of Animal Life. 2nd Ed., Oxford, p. 788. 



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