8 DEPARTMENT OF AGRICULTURE BUI.S. 1101-1125. 



Department Bulletin No. 1121, — The Effects op Inbreeding and Cross- 

 breeding ON Guinea Pigs: III. Crosses Between Highly Inbred 



Families — Continued. Page. 



Coat color 32 



Resistance to tuberculosis 32 



Early views on inbreeding 33 



Pre-Mendelian experiments 34 



Mendelian heredity and the problem of inbreeding 35 



Mathematical considerations 39 



Comparison of results with theory 45 



Summary and general conclusions 47 



Literature cited 59 



Department Bulletin No. 1122. — Absorption by Colloidal and Non- 

 coLLOiDAL Soil Constituents: 



Introduction 1 



Previous work 2 



Distinction between colloid and noncoUoid 3 



Outline of investigation 3 



Methods of determining absorption 4 



Estimation of noncolloidal absorption from soil fractions 5 



Methods of separating soil colloids 5 



Preparation of soil fractions 6 



Absorption by the fractions 6 



Estimation of noncolloidal absorption from mineral particles 7 



Preparation of mineral powders 8 



Absorption by the different soil minerals 9 



Absorption by the mineral particles in the soil 10 



Evidence concerning the nature of the soil colloids afforded by absorption 



data 13 



Absorptive capacities of mineral particles below 1 micron in diameter. . 13 



Absorptive capacities of synthetic gels 15 



General discussion 16 



Summary 17 



Literature cited 19 



Department Bulletin No. 1123. — Proportioning the Ingredients for 

 Ice Cream and Other Frozen Products by the Balance Method: 



The balance method 1 



Five basic conditions 2 



How the ingredients are proportioned 2 



Examples 1 to 5 2 



Rough estimate for proportioning ingredients 10 



Adjustment of composition 11 



Department Bulletin No. 1124. — The Marketing of Mill Feeds: 



How feeds are sold by mills 2 



Handling of f eedstuffs by cooperative societies 9 



Trade rules 9 



Grades : 11 



How to study market conditions 15 



What to ascertain about prices quoted 17 



Feedstuffs laws 18 



Present needs of the trade 19 



Department Bulletin No. 1125.- — The Saidy Date of Egypt: A Variety 

 OF the First Rank Adapted to Commercial Culture in the United 

 States: 



Discovery of the commercial value of the Saidy A-ariety of date. 1 



Essential characters of a great commercial variety 2 



The principal commercial varieties of dates 2 



Character and early history of the Libyan oases, the home of the Saidy date. 3 



Early Egyptian knowledge of the date palm 3 



Accounts of oasis dates by modern travelers (i 



Quest for the ''Wahi" date by the United States Department of Agricul- 

 ture, proving the identity of the "Wahi,'' "Sewi," and Saidy dates. ... 13 



Importations of the Saidy date under various names 15 



The Saidy date as a commercial A-ariety 25 



Tempei-ature requirements of the Saidy date 27 



Resistance of the Saidy date to humidity and dew-point conditions 32 



Literature cited 34 



