128 K. V. KossiKOV 



by the altered forms, and also by the original forms and by 

 S. ellipsoideus and S. cerevisiae. 



Discussion 



The experimental data quoted above enable us to give a 

 positive reply to the question on the stability of directed 

 adaptive changes, which was raised at the beginning of this 

 paper. These changes take place under the direct influence of 

 the specific substrate, and are not only quantitative but also 

 qualitative, i.e. they lead to the development of a new 

 quality. This quality is expressed in the capacity to produce 

 active invertase (or maltase), hydrolyse and ferment sucrose 

 (or maltose), retain this capacity and transmit it to the 

 progeny. It should be pointed out that in the investigations 

 of Oparin, Helman and Elpiner (1954), on extracts of S. 

 glohosus cells subject to the action of supersonic waves, it was 

 possible to detect very small quantities of invertase. This 

 experiment confirmed the data obtained by Yurkevitch (1950), 

 that active invertase is not found in intact cells and after 

 short autolysis. The appearance of invertase due to the 

 influence of supersonic waves is explained by Oparin, Helman 

 and Elpiner as the freeing of invertase from stable compounds 

 of the protoplasm. The hydrolytic activity of the enzyme is 

 completely inhibited in the process of growth and reproduction 

 of cells. Oparin, Helman and Zhukova (1954), in further 

 investigations on cells previously adapted by the present 

 author to fermentation of sucrose, but trained on a medium 

 without this sugar, and subject to the action of supersonic 

 waves, found an invertase activity 20 times as great as that 

 which was found in the original cells not adapted to fermenta- 

 tion of sucrose but subject to the action of supersonic waves. 

 It should be noted that great changes occurred in the carbo- 

 hydrate content of the adapted cells. 



If we 'Consider the variations occurring in the organisms as 

 being directed ones, i.e. caused by changes in the conditions 

 of their development, this does not mean that we should 



