Mat 21, 1909] 



SCIENCE 



825 



tte enzyme action of the eggs by virtue of the 

 presence of the enzymes of the spermatozoa. 

 If such were the case the accelerated enzyme 

 action might be demonstrated in the test-tube. 



The results of the tests were in no measure 

 conclusive, and the writer had hoped that he 

 would have an opportunity to pursue the prob- 

 lem further, and for these reasons no reports 

 on the investigation were made. As it seems 

 that the work in which the writer is now en- 

 gaged will prevent his having opportunity to 

 repeat the experiments, a succinct general 

 report of the work will here be made. 



Star fish were chosen because they afforded 

 a plentiful supply of both eggs and sperm, and 

 because they were easily obtained from the 

 waters about Woods Hole. The males and 

 females were carefully washed and kept sepa- 

 rate. The eggs and sperm were thoroughly 

 ground by mortar and pestle; the power of 

 each to split starch, fat and hydrogen dioxide 

 was tested. Three tubes were used in each 

 case. In tube 1 was placed 5 c.c. of ground 

 eggs, 5 c.c. of starch solution and 5 c.c. of 

 water. In tube 2 was placed 5 c.c. of ground 

 sperm, 5 c.c. of starch solution and 5 c.c. of 

 sea water. In tube 3 was placed 5 c.c. of the 

 ground eggs, 5 c.c. of the ground sperm and 

 5 c.c. of the starch solution. The tubes were 

 allowed to stand at room temperature for a 

 considerable time, after which the contents 

 were tested for sugar by the reduction test. 

 It was found that there was only the slightest 

 trace of reducing substance in tubes 1 and 2, 

 whereas in tube 3 there was a very distinct 

 amount present. These experiments were re- 

 peated perhaps six to ten times and the results 

 were conflicting. They were neither consist- 

 ently negative nor consistently positive. Nor 

 were they sufSeiently often positive to con- 

 vince one that when they were positive it 

 was not an accident. Comparable experiments 

 to the above were carried out with butyric 

 ether and hydrogen dioxide. The results were 

 equally exasperating as those with starch. 

 Whether the positive results were entirely the 

 result of error or whether the negative results 

 were due to the use of unmatured eggs or 

 sperm it is impossible to say. It seems, how- 

 ever, that the results were such as to justify a 



careful repetition of the experiments, and it 

 is hoped that some capable man who is inter- 

 ested in the problem will take it up. 



It is a well-recognized fact that a large 

 nimaber of the female star fish contain a large 

 number of eggs that appear in every way nor- 

 mal, mature and ready for fertilization and 

 yet will not develop when sperm is placed with 

 them. It seems that it may be possible that 

 this would account for the varying results. 

 Orville Harry Brown 



note on the accessory cleavage in the 

 hen's EGG^ 



Harper^ has shown that polyspermy norm- 

 ally occurs in the pigeon's egg. His figures 

 indicate that from twelve to twenty-five sperm- 

 nuclei are formed in the egg. Only one of 

 these, however, becomes a functional sperm- 

 nucleus ; the others migrate from the points of 

 entrance to the periphery of the disc where 

 they become active, dividing and giving rise 

 to the " accessory cleavage." There is thus 

 formed around the primary cleavage, which is 

 produced by the divisions of the segmentation 

 nucleus, an area of small cells. Blount' has 

 later shown that these supernumerary sperm- 

 nuclei live but for a short time, and then 

 degenerate. She estimates the time of their 

 disappearance as coming between ten and 

 twelve hours after fertilization. 



In the hen's egg accessory cleavage has 

 neither been figured' nor described. On taking 

 up. the study of the early development of this 

 egg I was, therefore, greatly surprised to find 

 an accessory cleavage. Not only can the fur- 

 rows be seen in the living egg, but I also have 

 preparations of surface views in which they 

 stand out with diagrammatic clearness. 



^Publications from the Zoological Laboratory 

 of the University of Texas, No. 96. The writer is 

 greatly indebted to the trustees of the Elizabeth 

 Thompson Science Fund for a grant with which 

 to carry on this work. 



= E. H. Harper, " The Fertilization and Early 

 Development of the Pigeon's Egg," Ainer. Jour, 

 of Anat., Vol. III., No. 4. 



' Mary Blount, " The Early Development of the 

 Pigeon's Egg, with Especial Reference to the 

 Supernumerary Sperm Nuclei, the Periblast and 

 the Germ Wall," Biol. Bull, Vol. XIII., No. 5. 



