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SCIENCE PROGRESS 



the following scheme for the derivation of the energy of the 

 sponge Sitberites'. 



From this scheme it appears that the animal obtains about 

 32 per cent, of its energy from oxidation reactions, and about 

 68 per cent, from processes of the fermentation type. 1 



It will be seen from the above figures that the intensity 

 of metabolism in the animals studied is notably influenced by 

 change of temperature, increasing with increase of the latter 

 factor. This is, of course, what we would expect, but the 

 figures also show that the character of the reactions involved 

 also changes with the temperature ; thus the respiratory 

 quotient falls as the temperature rises, indicating that in the 

 latter condition the oxidation process becomes more prominent. 

 Another of Putter's results is much more unexpected : he found 

 that the intensity of light also affected the rate of metabolism. 

 In a series of estimations of the rate of absorption of oxygen 

 the following figures were obtained 2 : 



Thus something analogous to the photo-synthetical reaction 

 of the typical green plant is also displayed by the sponge. 

 It is true that photo-synthetical reactions are carried out by 

 many animals, such as corals, alcyonaria, turbellaria, and 

 isolated species among other groups, but in such cases we 

 can trace the formation of starch from carbon dioxide and 

 water to the included algal corpuscles which arise by the 

 infection of the tissues of the animal by the pelagic cells of 

 Zoochlorellae. It is indeed not impossible that the sponge 

 investigated by Putter may have been infected in some such 



1 Vergl. Phys. Stoffw. p. 42. " Ibid. p. 31. 



