942 BIOLOGICAL EFFECTS OF RADIATION 



with the idea of secondary radiation (see page 932). If isolated organisms 

 in bouillon, for instance, excite secondary radiation in the medium, and 

 this secondary radiation is more intense than the primary radiation, we 

 should expect to have here very quick growth, more so than in dense 

 suspensions. 



Very much work has been reported on invertebrates, since invertebrate 

 material lends itself very well to experimental investigation. The 

 material has been used as sender as well as detector. To judge from the 

 illustrations giving experimental arrangements, it appears to be very 

 difficult, to say the least, to get uniform results. To many investigators 

 working in this field it seems that many experimental difficulties which 

 usually handicap the work of other investigators have apparently been 

 ignored by those reporting success in mitogenetic work. Magrou, 

 Magrou, and Chougroun (183) reported successful work, but later this 

 was attacked by Chougroun (49, 50). Apparently insufficient precau- 

 tions had been taken against chemical or spurious electrical effects. 



Sea-urchin eggs are very good senders for a certain time after fertiliza- 

 tion (65, 77), that is, the time for which Warburg has reported a very 

 large increase of oxygen consumption. Gurwitsch (108) believes that 

 here, too, we have a mitotin-mitotase process which is the source of the 

 radiation. 



Axolotl larvae up to 1 cm. are good radiators. Apparently here the 

 brain is the source of the radiations (Anikin, 3). A pulp made of brain 

 tissue will radiate while a pulp from the rest of the body will not. Devel- 

 oping Drosophila eggs are good senders (Wolff and Ras, 310). 



In a large number of papers, Blacher and his coworkers (21 to 26, 35, 

 147, 173) report the resorption process as a source of mitogenetic radia- 

 tion. Gurwitsch (108) states that there are three proofs which Blacher 

 has brought for his contention: (a) the appearance of mitogenetic radia- 

 tion during the metamorphosis of the insect egg (Drosophila); (h) the 

 relation between natural (induced) and forced metamorphosis of amphibia 

 and mitogenetic radiation ; and (c) the relation between wound products, 

 wound healing, and mitogenetic radiation. Embryonal stages of higher 

 animals, chicken embryos, especially, have been investigated. Brain 

 tissue of embryos will not radiate (Kisliak-Statkewitsch, 155, 108) but the 

 yellow of the egg incubated for 2 to 3 days makes a good sender. 



Positive success with the effect of mitogenetic rays on tissue cultures 

 has been reported by Chrustschoff (52) and others (214). However, 

 against their work stands a number of experiments (312) where negative 

 results are reported. 



A large number of authors (31, 85, 89, 114, 169, 175, 214, 216, 245) 

 report on the mitogenetic radiation of the blood and of organs which 

 depend on blood radiation. Blood from many normal or healthy animals 

 is reported to radiate in vivo and in vitro, if handled properly. Circulat- 



