Modificatiou of Gcrniuial Constiliilioii of Organisms 20] 



The well-organized experiments of Buchanan with Strep- 

 tococcus lacticus are quite characteristic of the general 

 results obtained in the in\'estigation of this problem in 

 unicellular plants. His conclusion that fluctuations cannot 

 be fixed in bacteria, whether normal or induced, is in accord 

 with most of the experiments of bacteriologists; neverthe- 

 less, this result is opposed by man}- records, believed to be 

 accurate, of sudden permanent departures in form and 

 function, especially in the yeasts. 



After a comprehensive survey of these studies upon 

 bacteria, Pringsheim concludes that while changes in yeasts 

 and bacteria have often resulted from the unusual action of 

 culture media, toxic solutions, temperature, etc., the modi- 

 fications of form and activit}' are diverse, and are either 

 permanent or transient. Especially difficult, however, if not 

 impossible in these organisms, is the attempt to separate 

 somatic and germinal effects, and much reasonable doubt 

 exists as to its possibility. The important contribution fr(}m 

 this work with bacteria and yeasts is the precise demon- 

 stration that the departures are readily produced, and 

 are a direct result of the incident external forces used, e\-en 

 in the simplest known organisms. 



Other low plants, such as algae and fungi, have often 

 been subjected to exciting agencies, and while changes have 

 resulted, these, like the modifications in bacteria, are usually 

 transient and not permanent. It would seem that these 

 simple forms ought to provide good material for the stud>' of 

 this problem, although it is possible that the low differentia- 

 tion between soma and germ ma}' introduce experimental 

 difficulties yet to be overcome. 



In higher plants the observations of Zedebauer with 

 Capsella are of interest, and introduce observations which 



