definitions are hardly necessary and do not contribute anything principally 



new for the understanding of the specificity of parasites for their hosts. 



One can agree that the definition of V. A. Dogiel is not accurate but there 



isn't the slightest basis to say that it is erroneous. If one is to examine p, 285 



"the new" definitions from the same point of view from which their authors 



consider them we will be able to detect therein erroneous statements which 



appear as a result of excessive degrees of caution of the authors attempting 



to underline their dialectico-materialistic understanding of the phenomena and 



processes. 



Insisting that occurrence is a realization of the potential possi- 

 bilities of existence on a given host we are not inclined to consider it only 

 as a result of the realization of specificity. In complex interrelations of 

 the biocoenotic pair, parasite -host, numerous interactions often take place, 

 interactions which are conditioned by peculiarities of the host and of the 

 medium which plays a role of no less importance in the realization of the 

 possibility of existence of a determined pair, parasite-host, within given 

 historical conditions. However, drawing the picture of the correlations 

 of specificity and occurrence schematically, we can say with certainty 

 that the latter is delimited more narrowly in connection with the circle of 

 the hosts than the former ^in spite of the fact that the manifestation of 

 occurrence is more complex by its nature than specificity. 



This thought is not new and was expressed in another form by 

 E. N. Pavlovsky (1946) in the shape of a formula: "the circle of potential 

 hosts of polyphagous parasites is much wider than the specific variety of 

 actual hosts" and J. D. Kirchenblatt (1941) "potential specificity is much 

 w^ider than the real. " 



Speaking about specificity one must underline that by it we 

 understand the phenomenon wherein the parasite, finding itself on or in the 

 host, develops normally in it and exists in contrast to those cases when the 

 parasite, even though it survives in a certain host, is not in a condition to 

 continue further normal development, reproduction, etc. therein. Cases 

 like the latter which are rather well-known should be indicated by sonne 

 other term, (perhaps, nobis) "pseudospecificity" or some other way. 



Before speaking about the process of the establishment of 

 specificity of the parasites for their hosts it is also Indispensable to note 

 that the scope of specificity is a specific indicator (characteristic, nobis) 

 of a given parasite. In the works of the majority of preceding researchers 

 this is implied but not clearly shown. Thus, even in some of the important 

 works of V. B. Dubinin and S. S. Shulmann about the specificity of separate 

 groups of parasites there is not a single line specifically dedicated to the 

 examination of this question (Dubinin, 1950; Shulmann, 1954b). Moreover, 

 V. B. Dubinin does not examine this question in his works which are 

 especially devoted to the question of determining the species in parasitic 



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