146 



THE MITOCHONDRIAL CONSTITUENTS OF PROTOPLASM. 



(a) We may inquire whether there is any relationship between the number of 

 mitochondria and the respiratory exchange of different organisms. Table 4 is 

 a portion of a table compiled by Krogh (1916, p. 148) relating to certain insects. 

 It shows a tremendous variation from as much as 82 to 1.45 calories per kilogram 

 per hour. Yet a comparison of the mitochondria in the two has not been made. 



Table 4. — Metabolism of cold-blooded animals at about 20° C. 



(b) Similarly for the oxygen consumption of tissues (Bayliss, 1915, p. 612) : 



Lungs, 0.01.5 c.c. per gram per minute. 

 Submaxillary gland, 0.027 to 0.089 c.c. per minute. 

 Suprarenal gland, 0.045 c.c. per minute. 



The oxygen consumption of the submaxillary gland is about twice that of 

 lung-tissue and the suprarenal four times. Roughly speaking, it is true that the 

 mitochonch-ia are relatively less abundant in the lungs than in the submaxillary 

 gland, but I do not think that there is any great difference between the suprarenal 

 and the submaxillary, at least in the mouse. 



Ehrlich has made a study of the oxygen saturation of organs by another and 

 less satisfactory method. According to him the organs may be divided into three 

 groups (quoting from Bayhss, 1915, p. 595): 



"1. Those of high 'oxygen saturation,' in which indophenol blue is not reduced, such 

 as the grey matter of the brain, the heart and some other muscular organs. 



"2. Those which reduce indophenol blue, but not alizarin blue. Such are the greater 

 number of the tissues, smooth muscle, most voluntary muscles and secreting glands. 



"3. Those which reduce even alizarin blue— lungs, liver, fatty tissue, Harderian gland.' ' 



Personally, however, I have been unable to find any correspondence between 

 the amount of mitochondrial substance and these figures of oxygen saturation. 



(c) Within single cells also attempts have been made to measure oxidations. 

 For example, R. 8. Lillie (1913, p. 247) finds that "in frogs' blood-corpuscles 

 the formation of indophenol by the intracellular oxidation of a mixture of alpha- 

 naphthol and dimethyl-para-diamino-benzene takes place most rapidly in the imme- 

 diate neighborhood of the nuclear and plasma membranes. The conditions at the 

 surfaces of these structures are thus |)articularly favoral)le to rapid oxidations." 

 One might expect to find condensations of mitochondria in these localities, but I 

 have carefully examined mitochondria vitally stained with janus green in frogs' 

 red blood-corpuscles and I have found that they are distributed more or less uni- 

 formly throughout the cytoplasm. 



