POSTNATAL GROWTH AND VARIABILITY OF THE 



BODY AND OF THE VARIOUS ORGANS 



IN THE ALBINO RAT 



C. M. JACKSON 



The Anatomical Laboratory of the University of Missouri 



SEVEN FIGTJBES 



CONTENTS 



Introduction 2 



Material and methods 3 



Growth and variability of the body 8 



1. Growth in body weight 8 



2. Variability in body weight 11 



3. Fraternal variability 16 



Growth and variability of the individual organs 20 



1 . Head 20 



2. Central nervous system 21 



3. Eyeballs -23 



4. Thyroid gland 25 



5. Thymus 26 



6. Heart 27 



7. Lungs J 31 



8. Liver , 33 



9. Spleen 34 



10. Stomach and intestines 35 



11. Suprarenal glands 36 



12. Kidneys 38 



13. Gonads 39 



a. Testes 39 



b. Ovaries 40 



14. General considerations 41 



Summary 48 



Bibliography 50 



Tables 53 



THE AMERICAN JOURNAL OF ANATOMY, VOL. 15, NO. 1 

 JULY, 1913 



