100 CARNEGIE INSTITUTION OF WASHINGTON. 



in our collection and her preliminary report on a spina bifida monster 

 has been published. The completed paper will soon appear in the 

 Contributions to Embryology, vol. vii. Dr. Abram Kerr, professor 

 of anatomy at Cornell University, spent this spring at the Laboratory, 

 completing a study of the brachial plexus. Dr. J. Whitridge Williams, 

 Dean of the Johns Hopkins Medical School, is collaborating with me 

 in a study of human implantation, our collection being especially rich 

 in suitable specimens for such researches. Dr. Edmund V. Cowdry, 

 professor-elect at the Peking Union Medical College, China, will 

 continue his work on mitochondria during the coming year. Professor 

 G. W. Bartelmez, of the University of Chicago, was with us in Sep- 

 tember of last year, preparing for publication a study of human 

 embryos less than 2 mm. long, in collaboration with Professor H. M. 

 Evans. A preliminary report of this work has been pubUshed. 



The following investigators have been with us for shorter periods : 

 Professor B. F. Kingsbury, of Cornell University ; Professor H. D. Senior, 

 New York University; Dr. F. P. Reagan, Princeton University; Mr. 

 E. H. Norris, University of Minnesota; Dr. Robert Chambers, Cornell 

 University; and Miss Marion Hines, of the University of Chicago. 



The collection was used also by Dr. Edwin G. Davis for the study of the 

 early development of the ureter, in collaboration with Professor Hugh 

 H. Young, director of the James Buchanan Brady Urological Institute. 



Several circulars of appeal for laboratory specimens have been issued 

 during the year to the medical profession. One of these described the 

 department; another, the classification and preservation of the speci- 

 mens; and a third, the laws of the State of Maryland relating to the 

 collection and disposal of abortion material. The second circular cites 

 our reasons for adopting the present system of classification and it may 

 be interesting to insert a table showing the main groups into which 

 we have classified our first 2,000 specimens. (See next page.) These 

 are arranged in series of 100 each, which we designate as centuries. 



As may be noted from the table, the specimens are first divided into 

 two main divisions — ^pathological and normal. Under pathological 

 are seven subdivisions. The first includes all specimens in which only 

 villi are found, the main body of the ovum having disintegrated; in 

 the second group the embryo and amnion are both missing, the chori- 

 onic sac having within it only the coelom filled with magma; in the 

 third the amnion is present but the embryo is not; in the fourth the 

 embryo has been reduced to a small nodule ; in the fifth the embryo is 

 cylindrical in form but very decidedly atrophic ; in the sixth the embryo 

 is quite well formed but markedly stunted; the seventh group is com- 

 posed mostly of larger specimens, including fetus compressus and 

 macerated embryos. The second division includes embryos normal in 

 form, and these are arranged in months, according to measurements 

 pubUshed in the Manual of Human Embryology, edited by Keibel 



