12 STMBIONTICISM AND THE ORIGIN OF SPECIES 



these observations the idea was advanced that mitochondria 

 play a role in heredity. Meves in particular has advanced 

 this theory. This conception finds a certain amount of 

 support in the views held by Wilson and Conklin who 

 recognize that the cytoplasm may play a role in hereditary 

 transmission. 



In 1894 Altmann expounded the doctrine '^Omne gran- 

 ulum ex granulo" fashioned after the well-known aphorism 

 of Virchow: "omnis cellula e cellula." Nmnerous studies 

 have since been made in an attempt to determine the manner 

 in which mitochondria increase in the cell. Duesberg, 

 Meves and many others have observed what they regard as 

 mitochondrial division, and believe with Guilliermond that 

 "the mitochondria result from the division of the preexisting 

 mitochondria of the egg, and that none of them arise 'de 

 novo' in the cytoplasm." Chambers ('15), on the other 

 hand, observed that mitochondria suddenly appear in the 

 cytoplasm and is against the idea of "mitochondrial con- 

 tinuity." It must be emphasized that other granules 

 besides mitochondria are supposed to be present in the 

 cytoplasm in many instances. While there is no occasion 

 to question Chambers' observations, there nevertheless 

 remain various possibihties in the interpretation of the 

 phenomenon. It is possible that the granules which were 

 observed to arise "de novo" in the cytoplasm have no rela- 

 tionship with the mitochondria. Cowdry has found that 

 the mitochondria sometimes go into "solution" in the cell. 

 My own observations (Wallin, '22) on the mitochondria of 

 lymphocytes, confirm Cowdry's observation. Under cer- 

 tain conditions of the cytoplasm, whatever they may be, 

 mitochondria are miscible with the cell cytoplasm. In 

 such cases the mitochondrial dye stains the entire cyto- 

 plasm. In fixed material, obviously, it is impossible to 

 determine if the mitochondrial material could again collect 

 into granules. Chambers' observation on the hving cell 



