112 CARNEGIE INSTITUTION OF WASHINGTON. 



von Alten, died during Easter week. However, during the summer 

 Professor Keibel's duties as a teacher have not been heavy, and as Dr. 

 von Lippman has been at Strassburg for the greater part of this time 

 it has been possible for them to continue their scientific work. Pro- 

 fessor Keibel, in collaboration with Dr. von Alten and Dr. Boeker, has 

 been engaged in the study of the structure and development of the 

 thymus gland, using for this purpose reptilian embryos collected by 

 Dr. von Gossler in the Dutch East Indies. A preliixiinary report of 

 Dr. von Alten's portion of the work, on the development of the branchial 

 pockets in turtles, has been published. In Chrysemis marginata inde- 

 pendent bodies develop from the fourth and fifth branchial pockets, 

 which subsequently unite with the supra-pericardial body, so that this 

 bod}' appears to arise from these branchial pockets. Partly for this 

 reason von Alten concluded that the supra-pericardial body arises from 

 a sixth branchial pocket, as is the case in teleosts and other animals. 

 Furthermore, he has shown that in the turtle the first three branchial 

 clefts give rise to organs — which fact is of importance, since various 

 authors believe that the thymus arises from such organs. Since the 

 death of Dr. von Alten the further study of this question has been 

 carried on bj' Professor Keibel on his own material as well as upon 

 specimens loaned by Professor Maximow of Petrograd. The work 

 of von Lippman on the development of the urogenital system in man, 

 although interrupted by the war, is nearing completion. 



I have formally transferred to the Department of Embryology my 

 collection of human embryos, which is the result of unceasing efforts 

 during the past twenty-five years. This collection consists of nearly 

 2,000 specimens, many of which have been prepared in permanent serial 

 sections. It is already unique both in magnitude and importance, but 

 a vigorous effort is being made to increase it still further. It is now 

 safely housed in fireproof rooms, together with the original data, 

 drawings, photographs, and clinical records, which are second in impor- 

 tance only to the specimens themselves. Convenient classified lists and 

 a card catalogue have been prepared in order to render all of this mate- 

 rial easily available. Circulars addressed to physicians setting forth 

 the needs of the department have been widely distributed and have 

 called forth a hearty response from the medical profession. These 

 circulars have also been referred to frequently in man\^ medical 

 journals in Asia as well as in this country. The Health Department of 

 Baltimore and the State Board of Maryland have cooperated most 

 generously by instructing all phj'sicians in the State to send such 

 specimens to our collection as could be obtained, and they have made 

 special regulations to facilitate this work. 



During the past year a number of memoirs have been submitted to 

 the Carnegie Institution of Washington for pubhcation. These are 

 brought out under the title of "Contributions to Embryology." 



