XXVIII 



THE PROBLEM OF MITOGENETIC RAYS 



Alexander Hollaender 

 Laboratory of Plant Physiology, University of Wisconsin, Madison 



Introduction. Characteristics of mitogenetic radiation. Earlier experiments of 

 Gurwitsch and others. Yeast as detectors of mitogenetic radiation. Bacteria as detectors 

 of mitogenetic radiation. Biological materials and experimental conditions. Physical 

 methods. Physical properties. Biological senders. Summary. References. 



INTRODUCTION 



It is now more than ten years since Alexander Gurwitsch (93) first 

 pubHshed his discovery of the so-called mitogenetic rays. He reported 

 in 1923 that these rays are given up by some biological materials, for 

 example, the root tips of onions, in certain stages of development; that 

 they pass through quartz, not through glass, that is, they lie in the 

 shorter ultra-violet; and that if they encounter other growing tissues 

 in certain stages of development, they produce effects in these which 

 are readily recognizable in the form of increased growth activity. 



Gurwitsch's pubUcations were at first almost entirely ignored. It 

 took several years before the scientific world as a whole took cognizance 

 of his work; and even now many of his critics feel that he has yet to 

 bring proof of the existence of the rays which he claims are causally 

 related to the effects produced. This is in spite of the fact that within 

 a 10-year period more than 400 articles dealing with the phenomenon 

 have appeared. 



By far the larger part of these publications has concerned itself 

 with the use of the mitogenetic-ray phenomena in studying biological 

 or chemical problems and only a comparatively few papers have dealt 

 with a critical evaluation of the methods of detecting the rays them- 

 selves. It is quite understandable that investigators who accept the 

 Gurwitsch phenomenon should no longer concern themselves with bring- 

 ing proof of its existence, but it is unfortunate that this fundamental 

 phase of the subject has been left in the main to those who criticize 

 adversely his findings. 



It is doubly unfortunate that the problem has attracted some workers 

 who, apparently, see in the problem only an opportunity to deal in the 

 spectacular. In some respects Gurwitsch, himself, is to blame for this. 

 He tends very pronouncedly to accept the work of investigators whose 

 data agree with his theories and to reject almost entirely criticism of a 



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