488 THE EXHIBIT 



2. At each of the several pillars. Demonstration devices for genetics. 

 Machines, instruments for illustrating the mechanics and mathematics of 

 genetic phenomena. 



(a) Mendelian ratios. Shot machine showing the Mendelian segregations and 



ratios in successive generations. 



Exhibited by: Harry H. Laughlin, Cold Spring Harbor, N. Y. 



(b) The pure sire method. Bead machine showing the elimination of mongrel 



chromosomes by the pure sire method. 



Exhibited by: Harry H. Laughlin, Cold Spring Harbor, N. Y. 



(c) Machine with bent rattan and pegs to illustrate the interaction of heredity 



and environment. 



Exhibited by: Harry H. Laughlin, Cold Spring Harbor, N. Y. 



(d) Shot machine to illustrate the reduction and segregation in gamete formation. 



Exhibited by: Harry H. Laughlin, Cold Spring Harbor, N. Y. 



(e) Shot machine showing the 10 modifications of the 9:3:3:1 ratio. 



Exhibited by: Harry H. Laughlin, Cold Spring Harbor, N. Y. 



(f) The Mendelian shovel — showing Mendelian ratios by random samplings of 



dried peas. 



Exhibited by: Harry H. Laughlin, Cold Spring Harbor, N. Y. 



(g) Dice-casting and pedigree selection. 



Exhibited by: Harry H. Laughlin, Cold Spring Harbor, N. Y. 



(h) Machine using colored cylinders and glass tubes to illustrate the mechanism 

 of Mendelian heredity showing segregation of chromosomes. 

 Exhibited by: Harry H. Laughlin, Cold Spring Harbor, N. Y. 

 (i) Spool machine and abacus showing chromosomal combinations in man. 

 Exhibited by: Harry H. Laughlin, Cold Spring Harbor, N. Y. 



(j) Spindle machine showing intra-chromosomal segregation and crossing-over. 

 Exhibited by: Harry H. Laughlin, Cold Spring Harbor, N. Y. 



(k) Trihybrid blocks. 



Exhibited by: Professor H. E. Walter, Brown University, Providence, R. I. 

 (1) Belt machine showing action of heredity and environment in determining per- 

 centage-incidence of goiter in the population. 

 Exhibited by: Dr. Charles B. Davenport, Cold Spring Harbor, N. Y. 



(m) Cord and roller machine showing maturation of sperm cells. 



Exhibited by: W. L. Wachter, Lafayette College, Easton, Pa. 



(n) Herediscope. A new device for demonstrating Mendelian heredity in plants, 

 animals and man. 



Exhibited by: The American Genetic Association, Victor Building, Wash- 

 ington, D. C. 



3. At the entrance to the Hall. Bust of Professor Henry Fairfield Os- 

 born, President of the Second and Honorary President of the Third Inter- 

 national Congress of Eugenics. Bust of Dr. Charles B. Davenport, Presi- 

 dent of the Third International Congress of Eugenics. 



4. The Average Man. A 22-inch statue by Mrs. R. G. Harris, based on 



