Febeuaky 18, 1921] 



SCIENCE 



167 



prime of his life, when his ability was entirely 

 obvious, James taught logic to beginners, extra 

 courses in Eadcliffe, and courses in summer 

 schools! Edward L. Thorndike 



SPECIAL ARTICLES 



NON-DISJUNCTION OF THK FOURTH 

 CHROMOSOME OF DROSOPHILA 



In Drosophila melanogaster the gene for 

 " eyeless " (e) and its normal allelomorph (E) 

 are situated in the small fourth chromosome, 

 l^ormal eye is dominant 



When heterozygous Ee normal flies are 

 crossed with eyeless ee, a ratio of 1 : 1 is ex- 

 pected. Actually this ratio is approached, 

 although the greater viability of the normal 

 type modifies the ratio to approximately 1.3:1. 



In a single mating of this sort a count of 

 171 normal to 206 eyeless was obtained. 

 Breeding tests of the descendants of this 

 mating indicate that in all probability non- 

 disjunction of the fourth chromosom.e has 

 taken place. 



If an Ee fly formed non-disjunctional 

 gametes Ee and — , the cross with an ee indi- 

 vidual would give rise to Eee flies. Here two 

 doses of " eyeless " meet one of " normal " 

 eye. The opportunity is given for an upset in 

 the balance of dominance between E and e. 

 The excess of eyeless flies, mentioned above, 

 suggests that such an upset has taken place. 

 Further matings make it appear that the Eee 

 form may be either normal or eyeless in aj)- 

 pearance, certain individuals being extremely 

 difficult to classify. 



In the course of the breeding work several 

 interesting results were obtained. Among 

 these was the isolation of eyeless flies, theo- 

 retically of the formula Eee, which when 

 crossed inter se or with other eyeless ee, gave 

 normal eyed progeny in considerable num- 

 bers. Eatios of 8, 9, 10 or even 12 normals 

 to 1 eyeless were also produced from matings 

 presumably EEe X Ee. Both these conditions 

 were expected on the hypothesis of non-dis- 

 junction. 



Using the appearance of eyeless flies as a 

 test, it seems that the mitosis of the Eee flies 



is in the vast majority of cases, if not always, 

 Ee and e ; while similarly that of the EEe flies 

 is Ee and E. 



The variation in somatic appearance of the 

 Eee form and the selective type of mitosis, re- 

 ferred to above, make it difficult to demonstrate 

 genetically the presence of EeEe individuals. 

 If flies of this type have occurred their mitosis 

 is commonly Ee and Ee. One mating only 

 indicates a possible exception to this type of 

 mitosis. This mating shows a peculiar ratio 

 possibly due to the presence of eee eyeless 

 forms. 



A further detailed report of the work will 

 shortly be published. I am greatly indebted 

 to Dr. E. G. Anderson for helpful suggestions 

 and discussion and to the Misses E. E. Jones 

 and D. M. Newman for assistance in the 

 laboratory. 



C. C. Little 

 Cold Spring Haeboe, N. Y., 

 January 6, 1921 



THE AMERICAN ASSOCIATION FOR 

 . THE ADVANCEMENT OF SCIENCE 



REPORT OF THE TREASURER FOR 1920 



In conformity with Article 2, Section 6, of the 

 By-Laws and by direction of the Council, the 

 Treasurer has the honor to submit the following 

 report for the period December 20, 1919, to De- 

 cember 23, 1920. 



The total cash receipts during the period in 

 question is $13,096.05. These include $4,381.21 

 from the W. Hudson Stephens estate; $1,850 from 

 32 Life Membership commutations, and $5,707.75 

 from interest on securities of the association. 



The total disbursements made during the period 

 in question amount to $10,272.56. These include 

 an aggregate of $4,500 for 19 grants authorized 

 by the council, and $4,431.31 paid for $4,500 face 

 value Victory Loan 4Jj^ bonds. 

 , The total amount of funds of the association 

 consisting of cost value of securities purchased, 

 appraised value of securities received from the Col- 

 burn Estate, and cash in banks, is $125,723.59. 



A balance sheet, shovriug assets and liabilities, 

 and tables showing details of receipts and dis- 

 bursements, are appended hereto. 



(Signed) Egbert S. Woodward, 



Dated December 23, 1920 



