174 



THE ENERGY OF THE LIVING PROTOPLASM. 



within a very narrow compass, since the difference becomes great 

 with an increased supply of oxygen. Hereby, the coal will burn 

 with much greater vigour, whilst respiration will not be in- 

 tensified, because the amount of oxygen needed is regulated by 

 the living cell (Pfliiger). 



The respiratory intensity not only exhibits great differences 

 in the various species of organisms,' 1 * but also in different organs 

 of one and the same organism. 



The intensity is greater in flowers than in leaves and 

 roots, (2) greater in leaves than in stem and fruits (Saussurc), 

 greater in light-plants than in shade-plants (Adolf Mayer), 

 greater in shoots of oil-seeds than in those of starch-seeds 

 (Godleivski) , greater in air-plants than in hydrophytes (Bochm), 

 in the cat double what it is in the sheep (Munch). 



While increase of pressure of oxygen will not influence the 

 intensity of respiration, the effect of rising temperature is, on 

 the other hand, very considerable, the activity of the protoplasm 

 being thereby greatly enhanced. At o° the respiration of plants 

 is very slight, at 17-20 0 it is already twenty times more intense, 

 and still gradually increases with the temperature nearly up to 

 that of death. Cold-blooded animals respire less than warm- 

 blooded, 131 while animals in hybernation exhibit a lower tempe- 

 rature and respire less than those in activity. 



Heat, visible motion, chemical action, and, in certain cases, 



(1) To-day it seems hardly credible that Liebig still maintained that chloro- 

 phyll bearing plants will not carry on respiration, although Saassurc had positively 

 proved to the contrary as early as 1805 ! Another erroneous conception, viz., that 

 the blood is the principal seat of respiratory oxidation in animals was corrected in 

 the year 186S by Pfliiger, who has recently told us what enormous labour for years it 

 took him to convince physiologists of the truth that oxidations in animals are 

 accomplished by the cells of the various organs. 



(2) The root-ends of young plants of Vicia Faba consume in 24 hours 5 per 

 cent of their dry matter (Palladia). Young rootlets and especially root-hairs have 

 an energetic respiration, while the interior of large roots respires certainly much less 

 than leaves. Not only the restricted access of air but also the lower temperature to 

 which usually roots are exposed in greater depth will under ordinary conditions 

 lower the intensity of respiration. 



(3) The intensity in frogs and earthworms is only about one tenth that in the 

 dog; that of higher plants is generally found less than that of warm-blooded animals, 

 in many cases also less than that of cold-blooded, if equal weights of dry matter are 

 considered. It is with pea-shoots about one half that of the frog, while in well 

 nourrished mould fungi it considerably surpasses even that of mammalia. 



