152 .Iori;.\AL ok tiik MrrciiKLi, Socikty [Dec. 



to the biological effects of radio-activity. Hertwig found that 

 the effects of the radium depend npon the strength and dura- 

 tion of the radiation. The effect of five minutes radiation of 

 the sperm was clearly recognizable in the resulting embryo. 

 Radiation of longer than five minutes always has a worse re- 

 sult until a certain low point is reached. This falls with in- 

 creased radiation up to one hour. From here on the develop- 

 mental curve begins to rise with increased radiation. Six 

 to twelve hours radiation of the sperm j)roduces astonishing- 

 ly pretty normal embryos. 



What action have the radium rays upon the sex cells to 

 account for the results ? Schwarz's and Schapcr's Lecithin 

 Hypothesis, i. e., that the injurious eftect is due to the de- 

 composition of lecithin, is insufficient. The lecithin hypo- 

 thesis has not been established by chemical analysis, and it 

 does not explain the results of fertilizing sound eggs with 

 sperm radiated different lengths of time. Sperm radiated 

 for five minutes cause very abnormal development, and in 

 this case a very small amount of destructive products of 

 lecithin would be added to the relatively immense mass of the 

 egg. 



Hertwig's theory is that by radiation with radium the 

 nature of the germ cells as living organisms is altered (made 

 pathological). In eggs fertilized with radiated sperm we 

 have a fusion of a sound and a pathological germ, and the 

 sick germ, the chromatin being chiefly important, acts as a 

 contaginm viviim (an infectious bacilhis). It causes ab- 

 normal development because in fertilization the pathological 

 male chromatin fuses with the egg nucleus and in all future 

 mitoses this pathological chromatin increases and is distrib- 

 uted to all the cells. In eggs radiated after fertilization we 

 get more aluiormal einln-oyos because both inatcM-nal and 

 paternal chromatin is made radium sick. That the proto- 

 plasm does not suffer so nnich injury as the chromatin seems 

 to be shown by the fact tliat tlie sperm loses its motility only 

 after verv lona' and intense radiation. 



