19 is] Death of Chicks ix Artificial Ixcubatiox 14:3 



calling for rapid breathing knows that this wonderful mechanism 

 cannot prevent weakness, which may be due chiefly to lack of needed 

 oxygen. 



This led to the investigation, the results of which are presented in 

 this paper. 



The author was so convinced of the correctness of his conclusion 

 that he proceeded at once to remove the occasion for the shortage of 

 oxygen, that is, the breathing chick. Before analyzing the air in 

 incubators, he constructed and operated an incubator designed to re- 

 move the chicks as rapidly as they were hatched. This incubator is 

 shown in the accompanying figure (PI. 9). 



A light in front of a glass window attracted the chicks toward the 

 front of the egg drawer as soon as they were out of the shell. In 

 their path was a hole cut in the floor of the egg drawer. Falling 

 through this hole and landing on a trap door in the floor of the incu- 

 bator, supported on delicately adjusted springs, they were emptied 

 out into the chute and soon found themselves in the brooder, where 

 they could breath all the oxygen they needed without robbing their 

 brothers in the eggs above. 



The results of these experiments are given in table I (experiments 

 F and G), and show marked improvement over those for the same 

 incubator under normal conditions. Unfortunately, this incubator 

 had a mechanical defect, which was considered important enough to 

 justify abandoning it. Before another was built it was thought more 

 practicable to try the application of oxygen. 



The results of the use of oxygen are reported in the table, experi- 

 ments H, I, J, and K. The author has been handicapped by the 

 limited number of experiments he is compelled to report, because 

 incubators were not accessible, but he feels that the results certainly 

 justify further experimentation. 



The analyses of air given in table 11 jioiut (Icfmitcly to the tact that 

 tliere is a shortage of oxygen, begiiining <'iii-ly in \\\r cigliircnth day 

 and reaching a point below fifteen ])('r cent. Some piiysiojogists be- 

 lieve that animal vigor and health will be rai)i(llv impaired in an 

 atmosphere of low oxygen content. 



