GENERAL PHYSIOLOGY 17.") 



for example, by an ingenious method, made out that a single Para- 

 mecium consumes 0.0052 c.mm. of 2 in one hour at 21° C, a 

 figure which Howland (1931), using the same method, slightly 

 modified, changed to 0.00049. Adolph (1929) made out a typical 

 rate of 0.55 cc. of oxygen intake per million individuals per hour 

 at 19.7° C, 



In a similar way R. Emerson (1929) obtained results with Amoeba 

 proteus and Bkpharmna undulans; Peters (1921) with Colpidium 

 colpoda; Hulpieu (1930) with Amoeba proteus found that the rate 

 of movement is not noticeably affected by changes in the amount 

 of available oxygen from 0.005 to 100 per cent ; below or above these 

 limits the animals are slowly killed. He found, furthermore, that 

 amebae are able to move for some time in the absence of oxygen 

 #vhich indicates that its energy is not derived by direct oxidation. 

 Verworn (1896), on the other hand, found that Rhizoplasma kaiseri 

 in an oxygen-free medium ceases its centrifugal pseudopodial move- 

 ments while centripetal movements continue for some time but 

 ultimately stop. Addition of oxygen restores both types. 



It is the function of catalytic enzymes to expedite chemical 

 processes which are under way and catalases of different kinds 

 result from metabolic activities going on in protoplasm. Amongst 

 these are the oxydases which aid in oxidation and reduction in 

 the cell. Indications of such agents as the "reducase" of Becker 

 (1926) and the extraction of glutathion have been obtained, while 

 Joyet-Lavergne (1929) adduces considerable evidence in support 

 of his view that glutathion is intimately associated with the mito- 

 chondria of the cell. 



Correlated with the intake of oxygen is the output of C0 2 and 

 water. While these are perhaps more properly treated in connection 

 with the functions of excretion there is good evidence of a gaseous 

 exchange, but quantitative results are not altogether satisfactory. 



The energy of combination, released by oxidation, is paid for by 

 loss in the chemical compound oxidized. Other compounds may 

 be formed with lessened energy of combination, and end-products, 

 notably C0 2 and urea ((NH 2 ) 2 CO), are not only useless to the organ- 

 ism but positively harmful unless voided. Excretion, therefore, 

 must follow oxidation. To make good the loss of substance new 

 food materials must be taken in, digested and assimilated, but this 

 is possible only through movement, and movement in turn is an 

 expression of irritability. Excretion and irritability thus are funda- 

 mental vital functions, while a third, nutrition, is closely correlated. 

 Excess of food intake over waste by oxidation leads to growth of 

 the diverse protoplasmic substances and to their reduplication by 

 division, while the aggregate of such divisions, expressed visibly 

 by division of the cell, constitutes reproduction. The funda- 

 mental vital functions are intimately bound together; external con- 



