348 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN 



hat aber wohl allgcmein gcglaubt, diese Differenzen seien im 

 Protoplasma, spezieller im Idioplasma, noch spezieller im Idio- 

 plasma des Kernes zu suchen. Demgegeniiber haben nun die 

 vorliegenden Untersuchungen mit Notwendigkeit zu der Annahme 

 gefiJhrt, dass losliche und diffusible Stoffe Trager der individuellen 

 Differenzen sein konnen" ('07, p. 112). Jost further suggests 

 the relation of these soluble substances to such specific sub- 

 stances as exist in the blood, lymph, and secretions of animals, and 

 to the so-called antibodies which develop in the fluids of organisms 

 during the development of immunity. 



Jost thus relates the cause of self-sterility to a lack of differ- 

 entiation, which develops quite independently of the hereditary 

 functions of germ plasm and which is quite individual, and in 

 development is purely epigenetic. The assumed similarity in the 

 fluids of the sex organs and sex cells exists solely because they have 

 developed on the same plant. 



Morgan's ('04, '10) noteworthy work on the causes of self- 

 sterility in the usually self-sterile animal Ciona intestinalis gives 

 data which Morgan considers as evidence that the failure to self- 

 fertilize is due to cytoplasmic relations established in the indi- 

 vidual. Morgan's theory of sexual fusion is a chemical one; the 

 actual entrance of the sperm into the egg is held to be a result of a 

 chemical reaction which occurs at the point of contact, and that 

 this reaction is dependent on a constitutional dissimilarity of the 

 gametes involved. His results are in close harmony with his 

 general views that self-incompatibility is, in Ciona, due to physi- 

 ological processes quite individual in development and cyto- 

 plasmic in action, and that germ cells may be decidedly influenced 

 by such individual conditions irrespective of their own particular 

 idioplasmic composition. 



For the experimental studies the eggs and sperms were removed 

 from the animals and the results of self- and cross-fertilization 

 were studied in sea water quite free from influence of body fluids 

 and with a relatively small amount of body tissues in\olved in 

 the form of testa cells adhering to the eggs. Here, it would 

 apjjear, the processes of fertilization may be in some respects 

 simpler than in the higher plants where the relation of pollen 

 tubes and tissues of pistils precedes the fusion of sex cells. Morgan 

 was unable to remove the self-immunity of eggs to the sperm of 



