Depression of plasma alpha-tocopherol level in chicks infected with avian leukosis.

in the egg shells when the eggs were studied in UV-light (Fig. 1). Control eggs did not fluoresce. The concentration of oxytetracycline in the egg shell, albumen, and yolk was measured by UV-absorption spectrofluorometry (Hayes and DuBuy, 1964). Oxytetracycline was deposited mainly in the shell (0.182 ± 0.028 iig./gm., mean ± SD), and albumen (0.190 ± 0.030 !*g./gm.) whereas the yolk contained only traces of oxytetracycline. The dry weight of the control egg shells was 4.79 ± 0.39 gm. (mean ± SD). The dry weight of the egg shells showing fluorescence was 4.66 ± 0.63 gm. and 4.85 ± 0.41 gm. after tetracycline and oxytetracycline injections respectively.