THE MITOCHONDRIAL CONSTITUENTS OF PROTOPLASM. 147 



(d) Or we may ask whether, when we modify experimentally the rate of oxida- 

 tion, there is any change in the mitochondria. Warburg (1910. p. 313) found that 

 he could double the oxygen consumption of sea-urchin eggs by the addition of 

 small amounts of sodium hydroxide to the sea-water. Adrenaline increases the 

 oxygen consumption of tissues and cyanide inhibits it. Israel's (1891, p. 334) 

 account of changes in the bioblasts of Altmann (mitochondria) in the cells of the 

 kidney following experimental ligation of the renal artery deserves confirmation 

 and extension. He found that they reacted very quickly — that is to say, in the 

 course of several hours. Champy's description of the solution of mitochondria 

 through asphyxiation in the center of pieces of tissue, remote from the surround- 

 ing oxygen, grown in serum, may have more bearing upon the question. 



(e) It would be profitable also to inquire into the condition of mitochondria 

 in intestinal worms which are anaerobic and which normally live in the absence of 

 oxygen. Ascaris is a good example. According to Mathews (1905, p. 333): 



" The only difference between anaerobic and aerobic respiration is that the anaerobic 

 protoplasm is so powerful a reducing agent that it is able to drive hydrogen out of the 

 water, thus oxidizing itself without the aid of atmospheric oxygen to act as a depolarizer. 

 iErobic protoplasm being less powerfully reducing, requires the presence of more or less 

 oxygen to take care of the hydrogen. The difference between these different kinds of 

 protoplasm is exactly the difference between metallic sodium and metallic iron." 



If this be true we would expect the mitochondria to be of unusual abundance; 

 but Bayliss (1915, p. 611) does not seem to subscribe to it. As a matter of fact, 

 judging by the work of Romeis (1913a, p. 9) and others, the mitochondria in As- 

 caris do not seem to be pecuUar. Leeches can live for upwards of ten days in the 

 ab.sence of oxygen, yet the illustrations of Grynfeltt (19126, p. 263) of their mito- 

 chondria do not seem to show an\' noteworthy differences from those of other 

 annelids. The cells of the gas-bladder of fishes, wliich actually secrete oxygen 

 (Woodland, 1911, p. 225), constitute another field for study. 



(/) And finally, in the condition of acidosis, there is an inliibition of the respir- 

 atory oxidation. It may be induced experimentally in a variety of ways. In 

 some preliminary experiments which I have made with rabbits by poisoning with 

 illuminating gas I have failed to detect any alteration in the mitochondria of the 

 lymphocytes in the circulating blood stained w^ith janus green, and I think that one 

 would expect to find changes in them earlier than in the other tissues. 



While the hypothesis that the mitochondria are concerned in protoplasmic respi- 

 ration is very attractive and meets some of the reciuirements, it should nevertheless 

 be tested experimentally in many directions before it can be unreservedly accepted. 



But we can hope for a more accurate analysis along purely experimental lines 

 by altering the rate and condition of the various vital processes and noting the 

 effect, if any, upon the mitochondria. We must bear continually in mind the 

 difficulty of dissociating functionally between the mitochondria and their environ- 

 ment. A change in the mitochondria does not necessarily mean that they are 

 concerned in the process in question, for they may be purelj- passive agents, the 

 change in their appearance being entirely due to some alteration in the protoplasm 



