TENTH ANNUAL REPORT. 125 



the skeleton would be facilitated by more or less tracing' from the 

 radiograph and give greater exactness. 



A fresh specimen makes a more distinct radiograph than one 

 which has been preserved in alcohol, the tissues being less dense 

 and not shrunken by the preservative. 



In the radiographs of reptiles and batrachians sharper defini- 

 tion could have been secured by laying the specimens on the plates 

 dorsal surface down, thus bringing the vertebrae closer to the 

 dry plates. 



The stages of regeneration of lost parts could doubtless be 

 observed satisfactorily. 



The radiograph has also the advantage of being life size and 

 permitting of exact measurement. It may be reproduced by the 

 ordinary methods of illustration applicable to a photograph. The 

 labor and cost involved in the making of such a picture is of 

 course less than by the usual methods of skeletonizing and draw- 

 ing. The time saved is also important. It is not yet practicable 

 to use living specimens in taking the pictures. 



