July 19, 1921 scientific notes and news 317 



It was found that sex, age, rate of gain, and weight at inoculation made 

 very little difference in the length of life after inoculation, determining in all 

 less than 10 per cent of the observed variation. On the other hand, marked 

 differences in resistance were found among the inbred families. Inbreeding 

 itself was not a factor of great importance in increasing susceptibility although 

 of the greatest importance in isolating different degrees of resistance. Two 

 of the inbred families, with fifteen to twenty generations of exclusively 

 brothersister matings back of them, were superior to the control stock, while 

 three were inferior. The crosses between the families produced young which 

 were in general at least equal to the better of the two parental families. 

 Resistance is thus apparently dominant over susceptibility. There was equal 

 transmission from sire and dam and to progeny of either sex. In cer- 

 tain crosses, the progeny were markedly superior to either parent strain, 

 indicating that these strains were resistant for different reasons, each thus 

 being able to supply what the other lacks. Among the crossbreds over 30 

 per cent of the variation in length of life was determined by the amount of 

 blood of the best family, contrasting with less than 10 per cent determination 

 by age, weight and rate of gain combined, and leaving something over 60 

 per cent determined by conditions at or following inoculation. 



There was no relation between the rank of the inbred families in resistance 

 to tuberculosis and their rank in other respects, such as average weight, 

 fertility, and success in raising young. As in all of these cases, however, 

 the importance of inbreeding in isolating hereditary differences was brought 

 out by contrasting the marked differences among the inbred families and their 

 crosses, with the lack of appreciable correlation between brothers within the 

 random bred stock. (Author's abstract.) 



The paper was illustrated by diagrams and curves, showing the tendencies 

 discussed. 



A. A. DoOLiTTLE, Recording Secretary. 



SCIENTIFIC NOTES AND NEWS 



THE PROPOSED CENTRAL ENGINEERING SOCIETY IN WASHINGTON. 



The initial step toward the organization of a central engineering society 

 in Washington was taken by the Washington Section of the American So- 

 ciety of Mechanical Engineers at its annual dinner on June 9. The plan, 

 as outlined by Professor George A. Weschler, chairman, and A. R. Citey- 

 NEY, secretary- treasurer of the Section, suggested that a larger organization 

 be founded upon one of the existing societies as a nucleus, to be open to all 

 engineering and technical men in the city, and to be governed by a representa- 

 tive body nominated by the local sections of the various national engineering 

 societies. This plan is similar to that of the Academy and its Affiliated 

 Societies. 



Messrs. A. G. Christie and W. F. Ballinger reported on the experience 

 of the Baltimore and Philadelphia Engineers' Clubs, respectively. Mr. 

 L. W. Wallace, executive secretary of the Federated American Engineering 

 Societies, discussed the work of that organization. Dr. R. B. Sosman, 

 secretary of the Academy, spoke on the experience of the Academy in form- 

 ing such an organization. 



Informal views of the plan were also presented by the following repre- 

 sentatives of the Washington sections of the engineering societies: John C. 



