FUNCTIONAL SIGNIFICANCE — MITOCHONDRIA 427 



203; '14, p. 269), have all arrived at the conclusion that mito- 

 chondria are chemically a combination of phospholipin and 

 albumin, which, in itself, speaks very strongly in favor of the 

 unity of the class of granules under consideration. The evidence 

 is briefly this: 



1. Mitochondria are almost completely soluble in alcohol, 

 ether, chloroform and dilute acetic acid. They are rendered 

 insoluble by chromization. They are hot doubly refractile 

 and they do not stain with Sudan III or Scharlach R. They 

 are only sometimes blackened with osiTiic acid. 



2. It is said that part of the mitochondrial substance is not 

 soluble in these fat solvents and it is supposed that this portion 

 is albumin (see also Bullard '16, p. 26) for formalin and bichro- 

 mate, which are used as fixatives for mitochondria, are energetic 

 coagulants of albumin. Millon's reagent is the only color test 

 for protein which can be applied to material in sections. So far- 

 as can be ascertained^ it is negative, but this cannot be stated 

 positively because, even if there were a change in color, it might 

 not be of sufficient intensity to be appreciated in filaments of 

 such extreme fineness as mitochondria {0.2 /j. in diameter) em- 

 bedded in a colored cytoplasm. Mitochondria do not give any 

 of the color reactions of polysaccharides. 



3. Artificial mitochondria have been made by Lowschin of 

 lecithin, and albumin solutions (resulting in the formation of 

 lecithalbumin?) which apparently present the same form and 

 solubilities as true mitochondria. They form granules, rods 

 and filaments which multiply by division. He embedded them 

 in glj'cerin-gelatin, fixed them and found that they stained in 

 the usual way by the various mitochondrial methods.*^ 



This evidence is good (being apparently accepted by the 

 Kochs '13, p. 427 and Mathews '15, p. 102, as far as the phos- 

 pholipin fraction is concerned) but it cannot be considered as 



^ Bensley, personal communication. 



•^ Mayer, Rathery and Schaeffer ('14, p. 612) have been able to alter the mito- 

 chondria experimentally in liver cells. In stages with more mitochondrial sub- 

 stance chemical analysis shows an increase in phosphorized lipoid; in stages with 

 less, a diminution. 



