Retarded sexual maturity of turkeys following treatment 
with 0.011 per cent furazolidone was observed by Redman and 
Smyth (1957). Weiss et al. (1960) found that 0.04 per cent 
Nicarbazine retarded sexual maturity of White Leghorns. An- 
other pharmacological treatment is the use of anti-cock-rabbit 
serum reported by Belenjkii (1940); cited by Romanoff, (1960) 
as resulting in the absence of spermatogenesis and an increased 
amount of interstitial tissue in the testes. MTriethylenemelamine 
(TEM) at 0.2 mg.Jkg. daily for five days has a radiomimetic 
effect on spermatogonia in the male rat (Steinberger et al., 1959) 
and is currently being investigated at several laboratories as 
a bird sterilant. More promising perhaps than TEM are methylethane-~ 
sulphonate and methylmethanesulphonate which inhibit spermatids 
and spermatozoa (Jackson et al., 1961) thus acting quickly after 
administration. 
Te Short wave radiation. 
Yamamoto (1959) noted that irradiated fatty acid from 
liver given to rabbits caused the degeneration of germinal cells 
with the formation of giant cells or multinucleated cells and 
mitotic abnormalities. 
The male germ cells of the chicken appear not to be 
affected when the embryo is subjected, before incubation, to 
x-ray doses ranging from 40r. to 480r. or when doses of 100r. to 
400r. are given during incubation. However, in make chicks less 
than 3 weeks old, irradiated with dosages in excess of 200r., 
the division of spermatogonia was arrested, the nuclei of these 
cells became pycnotic and the cytoplasma was pale (Essenberg and 
Zikmund, 1938). In adult cocks nearly 1300r. was required for 
initial injury, revealed by pycnosis of the nuclei in primary 
and seoondary spermatocytes and by a decrease in the number of 
spermatids (Essenberg and Kanasch, 1940). Sturkie et al. (1949) 
found when x-rays are administered before sexual maturity, a dose 
of 2100r. is the minimum that prevents subsequent spermatogenesis 
in most individuals. They observed that within 14 days after 
administration of a sterilizing dose, degenerate spermatozoa 
were seen in the lumina of many tubules and within 25 days only 
one layer of cells remained lining the tubules. Regeneration 
of spermatogenic tissue does not occur. It is of interest to 
note that irradiation of cock semen in vitro with a dose up to 
10,000r. has been shown by Kostin, (1960), to have no detectable 
effect on the motility, respiration and anaerobic eal ogy 
although the fertilizing capacity is reduced (Mann, 1954). 
Ershoff and Brat, (1960), experimenting with rats, 
found that x-irradiation and gamma irradiation from a cesium 
137 source were comparable in effects upon the development and 
morphology of the reproductive system, both irradiations pro- 
ducing a significant degree of gonadal injury. 
80 
