EXPERIMENTAL EMBRYOLOGY 405 



but the whole plant to the chemical, resulting sometimes in mal- 

 formations of the leaves. It is possible, however, that certain sub- 

 stances may have a less toxic effect than others and with further 

 experience new formulae can be worked out which will induce a 

 satisfactory fruit set without causing injury to the rest of the 

 plant. 16 



Conclusion. Although experimental embryology is a new sub- 

 ject, it is already possible to recognize the fundamental problems 

 which confront it. Their solution will be difficult and will no 

 doubt demand many years of patient research, but this is pre- 

 cisely what makes the field so interesting and at the same time so 

 promising. While descriptive and phylogenetic embryology will 

 continue to stay, the future trend is clearly towards the experi- 

 mental side. Here we have the frontier state within whose borders 

 the geneticist, physiologist, cytologist, and embryologist all find a 

 common ground. 



References 



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 Anthony, S., and Harlan, H. V. 1920. Germination of barley pollen. Jour. 



Agr. Res. 18 : 525-536. 

 Banerji, I. 1929. Studies in cotton pollen. Agr. Jour. India 24: 332-340. 

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 Beth, K. 1938. Untersuchungen uber die Auslosung von Adventivembryonie 



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16 Howlett and Marth (1946) report that with greenhouse tomatoes a combina- 

 tion of /S-naphthoxyacetic acid, indolebutyric acid, and 4-chlorophenoxyacetic 

 acid is more satisfactory than other substances. 



