CHAPTER XVI 



THE MARVEL OF GROWTH 



Dr. Minot studied chicks from the time they began to 

 develop within the eggshell until the last bit of down was 

 laid in place, until the shell was packed to its utmost limit 

 with a living chick, until hatching time had come. To do 

 this he took eggs that were set for hatching, broke one on 

 each successive day, and examined the contents both with 

 the microscope and with the naked eye. 



He also took frequent photographs of the progress of these 

 developing chicks. In this way he followed them step by step 

 as the bundles of the cells grew bigger, and we have the 

 printed record of what he found. 



First day, " A mere gathering of cells." 



Second day, " The chick has distinctly a head and a little 

 heart." 



Third day, " The eye has developed, the heart has become 

 large, the tail is projecting, the dorsal curve of the future 

 neck is distinguishable." 



Fourth day, "" It is a strange-looking beast, with a wing 

 here and a leg there, a little tail at this point, an enormous 

 eye, almost monstrous in proportion, and, finally, a great 

 bulge caused by the middle division of the brain." 



Fifth day, " We now have a chick the brain of which is 

 swelling, causing the head to be of so queer a shape, with 

 the eye that seems all out of proportion to the rest of the 

 body, that it imparts an uncanny look to the embryo. The 



