This study was supported by Grant #D-1146(CL) National Institutes of Health.

Presented before the North Atlantic Component of The Edward H. Angle Society of Orthodontia.

*From the Department of Orthodontics, Temple University.

*From the Child Study Clinic, University of Oregon Dental School.

This investigation was supported in part by Grant HD 00157-06 from the Institute of Child Health and Human Development, National Institutes of Health.

*Dental Materials Department, Indiana University School of Dentistry. This research supported in part by Research Grant D433 from the National Institutes of Health. U.S. Public Health Service.

Shown before the Univ. of Illinois Alumni Society, March 1964.

The opinions or assertions contained herein are those of the author and are not to be construed as official or reflecting the views of the Department of the Navy, or the Naval Service at large.

Presented before 1st Inter-American Orthodontic Seminar, Los Angeles, California — Mazatlan, Mexico, June, 1964.

From the Philadelphia Center for Research in Child Growth. Financed in part by NIH Grant D87-C10-14.

This investigation was supported by research Grant 1901FR0547-01 from the National Institute of Dental Research, National Institutes of Health.

Read before the Southern California Component of the Edward H. Angle Society of Orthodontia, Pasadena, California.