864 RADIATION BIOLOGY 



irradiated (Murphy and de Renyi, Levine, Finkel, von Klot, Forsterling, 

 Linser and Helber). 



In almost all of the experiments, irradiation was administered from an 

 external source. The whole pregnant female was usually exposed, 

 although several investigators attempted to direct the beam to the abdom- 

 inal region. Shielding of extra-abdominal regions was part of the tech- 

 nique in experiments by Warkany and Schraffenberger (1947), Job et al. 

 (1935), Kaven (1938a, b), Murphy and de Renyi (1930), and Regaud 

 et al. (1912). Wilson (1949), and Wilson and Karr (1950, 1951) went so 

 far as to expose only selected embryos. Finally, Raynaud and Frilley 

 (1943a, b, 1947a, b, c, 1949a, b) used a beam of 0.5-3.0 mm diameter to 

 irradiate only selected parts of certain embryos. Radioactive isotopes, 

 Sr 89 and P 32 , were injected into the pregnant female by Finkel (1947) and 

 by Burstone (1951), respectively. Bagg (1922) and Gudernatsch and 

 Bagg (1920) injected a solution of sodium chloride which had been 

 exposed to 500 mc of radium emanation to obtain an "active deposit." 



A. THE PREIM PLANTATION PERIOD 



The rather scanty work on the preimplantation period is summarized 

 in Table 13-1. It may be noted, first of all, that none of the publications 

 report abnormalities while all report prenatal death. This result is par- 

 ticularly meaningful in the case of investigators whose work has also 

 extended into other periods. Thus Job et al. (1935), who obtained 

 abnormalities from the irradiation of later stages, report only resorption 

 as a result of 0.8 skin erythema dose (hereafter to be abbreviated to 

 SED) 2 delivered during the preimplantation period. The survivors were 

 normal. The similar contrast found by Russell (1950) in a survey of the 

 gestation period has already been mentioned. Kosaka (1928c) states 

 that % SED delivered during the preimplantation period to guinea pigs 

 has either no effect at all or kills the embryo. The normality of survivors 

 from very early irradiation (mice or rats?) extends even to normality of 

 postnatal development (Kosaka, 1928e). Parkes obtained litters from all 

 of ten females irradiated in the second and third weeks of gestation, but 

 only two out of thirteen irradiated during the first week carried to term. 



2 The SED is defined (Ellinger, 1941) as the quantity of radiation administered 

 at 23 cm focal skin distance, 180 kv, 0.5 mm Zn + 3 mm Al filter, and a field of 

 6X8 cm. This is equivalent to 600 r in air. However, the radiation factors in 

 most of the experiments using SED dosimetry differ from the standard conditions 

 enumerated and, since the r equivalent to 1 SED varies considerably depending on 

 hardness of radiation and other factors, the practice throughout this review has been 

 to cite the dose exactly as stated by the author. This applies also where other 

 systems of measurement have been used, such as the Holzknecht unit, or the pastille 

 tint method. It has been left to the reader to make attempts at approximate conver- 

 sion to r units in individual cases where it might be of interest and where the original 

 publication may be consulted for details on radiation factors. 



