134 THE MITOCHONDRIAL CONSTITUENTS OF PROTOPLASM. 



of reducing substances in the cytoplasm. These he beheves to be the mitochon- 

 dria on account of their hpoid characteristics. 



But it remained for Mayer, Rathery and Schaeffer (1914, p. 619) to furnish 

 detailed evidence in support of this view. They point out: (1) That mitochondria 

 are chemically well adapted to function in oxidations and reductions; they are 

 phosphatids, and phosphatids have the power of auto-oxidation (Mathews, 1915, 

 p. 97), though some (Bayhss, 1915, p. 592) tliink that they do not possess it to any 

 appreciable degree; according to Mayer, Rathery and Schaeffer, mitochondria 

 contain unsaturated fatty acids with ethylidene groups. These have a great 

 affinity for oxygen and oxidize themselves to aldehyde. (2) That agents which 

 attack lipoids (Uke alcohol, ether, and chloroform among the anesthetics) at the same 

 time cut down the respiratory oxidations. (3) That mitochondria are present in all 

 cells and that respiration is the most fundamental property of Uving matter, etc. 



Still more recently the Lewises (1915. p. 393) have arrived at much the same 

 conclusion from their studies on mitochondria in tissue cultures. It is in accord 

 also with my own observations on the staining of mitochondria with janus green 

 and related dyes (1916a, p. 429). 



XI. PATHOLOGY. 



Much more work has been done on mitochondria in pathological conditions 

 than is generally reahzed. It has been done from many points of view; it is widely 

 scattered, and some of it is very difficult of access. Moreover, it is not entirely a 

 new development, as many people suppose. We have to do with two mitochondrial 

 Uteratures, an old and a new. It is the old one which is so frequently ignored, an 

 outgrowth of Altmann's remarkable researches at Leipzig from 1880 to 1890; it 

 flourished for a while but was soon choked by the active criticism which his views 

 excited, for he thought that his "bioblasts" were the final ultimate Uving particles 

 embedded in protoplasm which he considered to be hfeless. 



The central thought which underhes all the recent work on mitochondria in 

 pathological conditions is the conviction that we now have at our disposal a new 

 criterion of cell activity and cell injury. We do not know it or understand it, but 

 it has been proven over and over again in the last few months to be of great and 

 surprising deUcacy, for it responds (even before the nucleus) to injurious influences; 

 and it has the rare merit of being cytoplasmic. We may expect environmental 

 changes to act on it which would make no impression at all upon the nucleus. It 

 is convenient to our hands in all cells and there is no knowing what story it will tell 

 when we ask it. 



In the study of mitochondria we are at once, and very forcibly, reminded of 

 bacteria. One has a feeling, in looking over mitochondrial preparations for the 

 first time, that aseptic precautions should have been taken in removing the tissues. 

 We can easily forgive Altmann for thinking that they were elementary organisms, 

 for the similarities between them and bacteria are really remarkable. Their form 



