436 E. Y. COWDRY 



The problem is evidently not a simple one. We must weigh, 

 with caution, assertions of the transformation of mitochondria 

 into other chemical substances, appreciating well the little 

 that is known of the chemistry of the processes involved. Mito- 

 chondria unquestionably are associated in some way with the 

 formation of many substances: 1 have emphasized the improb- 

 ability of their being transformed into them. Yet we must 

 not follow the regular plan, go altogether too far in our reasoning 

 and imagine that mitochondria never change, only it is likely 

 in some cases, in others it is not. It w^ould not require a great 

 stretch of the imagination to conceive of mitochondria as being 

 changed into lecithin (Bobeau '11, p. 393) or neutral fat (Dubreuil 

 '13, p. 142), though Leathes ('10, p. 115) suggests that the re- 

 verse is true, that phospholipins are built up from neutral fat. 

 One is naturally inclined to consider most seriously those studies 

 (Chambers '15, Casteel '16) in which janus green is used with 

 living material because some of the so-called mitochondrial 

 methods are far from specific and are inclined to deceive the 

 unwary. 



RELATION TO INHERITANCE 



Benda and Meves were the first to claim that the mitochondria 

 may constitute, in part, the material basis of heredity. The claim 

 is based on the well-known experiment of Godlewski which 

 seemed to show that an egg, deprived of its nucleus, when fertil- 

 ized with sperm of another species, retained certain maternal char- 

 acters on development. In fact there is nothing novel in the 

 conception that there is such a thing as a cytoplasmic heredity. 

 Jenkinson ('14, p. 152) and ConkHn ('15, p. 176) freely admit it. 

 What is new is the view that mitochondria carry it. Van der 

 Stricht ('09, p. 80) showed that the penetration of the sperm 

 into the egg is total in the bat. Moreover, there are the positive 

 observations of an ever increasing number of investigators that 

 paternal mitochondrial substance enters the egg on fertilization. 

 Space only permits of reference to Meves' demonstration of 

 this in ascaris ('11, p. 709), Levi's ui the bat ('15, p. 488) and 

 of Duesberg's in ciona ('15, p. 41). 



