DEPARTMENT OF GENETICS. 103 



(19) The publication, in cooperation with the Army, of the results 

 of anthropometric measurements of recruits and veterans; with ref- 

 erence to habitat, occupation, race, and associated diseases. 



(20) Evidence that abnormalities in development of pigeon embryos 

 are often due to endocrine disfunctioning of the mothers. 



(21) The elaboration of tables for predicting probable future egg- 

 production in the fowl from its fecundity at any time. 



(22) Evidence that alcohol tends to reduce the average size of litters 

 and the number of litters. But in later generations from alcoholized 

 rats the normal number of litters per rat may reappear, and may 

 even be exceeded, probably due to selective elimination by alcohol of 

 the weaker strains. 



(23) Alcoholized rats grow more slowly than the controls; but 

 their offspring grow more rapidly than the offspring of the controls. 



(24) Proof that (in swine at least) the migration of ova from one 

 ovary through the body-cavity to the opposite tube is rare. On the 

 other hand, there is a migration of ova within the uterus which 

 tends to secure a uniform distribution of embryos and to prevent 

 crowding. 



DETAILED REPORTS ON INVESTIGATIONS IN PROGRESS. 

 INTERCHROMOSOMAL MUTATION. 



The modern work on mutation dates from the publication of De 

 Vries's classic monograph, "Die Mutation theorie," 1901-03. This 

 study was based on the evening primrose {Oenothera lamarckiana) . 

 When De Vries gave the opening address at the Station for Experi- 

 mental Evolution in 1904, he expressed the hope and expectation that 

 his Oenothera work would be continued by this department (third Year 

 Book of the Carnegie Institution of Washington, pp. 48, 49). We 

 tried for some years to do this through the work of Dr. G. H. ShuU and 

 Miss Anne M. Lutz. Many others took up the work and, with the 

 departure of Dr. Shull, it was for a time abandoned here. With the 

 coming of Dr. A. F. Blakeslee the search for genetically simpler mutat- 

 ing plant material has been continued, and has now been rewarded by 

 finding it in Datura stramonium. This species has only 12 pairs of chro- 

 mosomes, and its habit of growth is rather definite. In ease of guard- 

 ing the pollination it leaves little to be desired. The outstanding 

 feature of the species is that it, like Oenothera, is undergoing a 

 variation in its chromosome-complex; and with every variation in 

 its chromosome-complex goes a special somatic form. This depart- 

 ment is now fully launched on a program of work with this valuable 

 form, and we trust that with appropriate support the analysis of 

 De Vriesian mutation can be carried beyond anything hitherto 

 accomplished. 



