428 E. V, COWDRY 



absolutely conclusive because it is subject to all the multi- 

 tudinous objections, which are very justly raised, against the 

 results of analyses of intracellular material. As yet no direct 

 chemical analyses of mitochondria have been made. The eggs 

 of fishes may prove favorable material because they are fairly 

 large, and, since their cytoplasm is quite liquid, the mitochondria 

 can be easily collected in a compact mass to one side by centri- 

 fuging, and, perhaps, be dissected out or removed by means of 

 a capillary pipette. 



Hoppe Seyler pointed out that lecithin (a typical phosphohpin) 

 and cholesterol are to be found almost an3Awhere that life phe- 

 nomena exist. In fact a great wave of revived interest is mani- 

 fested in recent chemical and pathological literature in these 

 complex compounds of fatty acid, phosphorus and nitrogen. 

 Mathews very aptly says that the phospholipins are. the most 

 important substances in li\'ing matter: 



For they are found in all cells, and it is undoubtedly their function 

 to produce, with cholesterol, the peculiar semifluid, semisolid state 

 of protoplasm. The latter holds much water in it but it does not dis- 

 solve. Indeed it may be said that the phospholipins with cholesterol 

 make the essential substratum of living matter. — This physical sub- 

 stratum of phospholipin differs in different cells and probably in the 

 same type of cells in different animals, but everywliere, from the low- 

 est plants to the highly differentiated brain cells of manmials and of 

 man himself, it possesses certain fundamental chemical and phj^sical 

 properties. In all cases the phospholipin sul)stratum is soluble in 

 alcohol containing some water- ('15, p. 88). 



In view of these considerations it is interesting to enquire 

 whether the distribution of mitochondria in cells corresponds 

 with that of the phosphohpins. It is certainly true that mito- 

 chondria are more widely distributed than any other kind of 

 cytoplasmic granulation now known to us. They occur in 

 almost all cells. Certain cells, like the fully differentiated non- 

 nucleated red blood cell, undoubtedly contain a large amount 

 of phospholipin though no formed mitochondria can be seen. 

 The mitochondrial substance is probably present in solution 

 (Cowdry '16), because it would be obviously absurd to state 

 that it must always occur in a certain state of condensation 

 which makes it visible with the microscope. 



