100 CHARLES PACKARD 



c. The development of eggs radiated before fertilization with 



fresh sper77i 



In the second series of experiments the unfertiHzed eggs were 

 placed in a few drops of water in a watch glass. The glass tube 

 containing the radium was about 1 cm. in diameter and 1.5 cm. 

 in length. When this tube was set down into the water, the sur- 

 face tension of the water was sufficient to draw the eggs up along 

 the sides of the tube, thus distributing them fairly evenly, and 

 ensuring an equal amount of radiation. Control eggs were treated 

 in the same way except that the glass capsule, similar to the 

 radium capsule Was empty. In all of these experiments small 

 quantities of eggs were used. 



The unfertilized eggs, after two hours exposure to the radium 

 rays show no change in appearance. The germinal vesicle and 

 the alveolar layer are intact. High magnification shows no 

 alteration in the protoplasm, or in the oil and yolk spheres. When 

 such eggs are inseminated with fresh sperm many immediately 

 throw off the jelly in a normal fashion. As a consequence the 

 alveolar layer quickly disappears. The jelly is apparently normal 

 in consistency, and loses its mucilaginous character in about 

 fifteen minutes, just as with normal eggs. 



A considerable number of eggs, however, fail to extrude the 

 jelly at once and consequently cannot push away the great quan- 

 tity of spermatozoa that surround them, as can the normal eggs. 

 Polyspermy results in such cases, many eggs being penetrated by 

 a dozen sperm heads. Sections of such eggs show the alveolar- 

 layer still intact (fig. 9). This layer presents a fairly normal 

 appearance, with alveoli closely crowded together, but not always 

 radially arranged. Typically it extends entirely around the egg, 

 and is about six or seven /z in diameter. But in these eggs it is 

 very unevenly distributed, being sometimes absent altogether 

 from one side, and massed in a thick layer on the other. There 

 is no definite place at which the layer collects in these cases. 



The eggs showing this peculiarity are uniformly larger than nor- 

 mal, the increased diameter being due to the greater width of the 

 alveolar layer which varies from eight to fifteen n in thickness. 



