ly in the avian male reproductive tract subsequent to sperma- 
togensis. It does not seem unreasonable to expect that many 
such substances could be found. They might express themselves 
by inhibiting maturation of sperm, by reducing or inhibiting 
the development of motility, or by altering the seminal plasma 
produced by the seminiferous tubules and the epididymis. The 
effects of chemicals upon semen in vivo are amenable to various 
laboratory determinations of morphology, motility, relative 
numbers of spermatozoa, volume, viscosity, etc. that have been 
perfected for use in other animals. Kamar (1959) developed a 
method that differentiates living from dead sperms in fowl and 
that gives a preliminary picture of the viability and fertility 
of semen samples within minutes after semen collection. 
Jackson et al (1961) have shown that oral administra- 
tion of methylethanesulphonate and methylmethanesulphonate in- 
hibit fertility of spermatozoa in rats. The mode of action 
is unknown. 
2e in vitro. 
a) Effect of length of storage and storage temperature on 
undiluted semen. 
There have been many reports, some of them quite re- 
cent, indicating that storage of semen is highly deleterious to 
its fertilizing capacity. As a result, research has been directed 
towards finding the maximum time that semen can be held without 
total damage and towards finding the optimum temperature for 
such storage. 
Garren and Shaffner (1952) studied the effect of 
temperature and time of storage on the fertilizing capacity of 
undiluted fowl semen. They used New Hampshire chickens, storing 
semen at 0, 10, 20, 30, and 40 degrees Centigrade, and insemina- 
ting it at 90-minute intervals. In their work, the optimun 
storage temperature was found to be 10 degrees Centigrade for up 
to six hours of storage time. When stored at 15 degrees Centi- 
grade, fertility was maintained for three to four hours. Sperm 
stored at 0 and 5 degrees Centigrade showed the best retention. 
of motility but their fertility dropped sharply after a few — 
minutes of storage. The fertility of fresh semen was consiste 
ently better than that of stored semen. 
Somewhat similar results were found by Hunsaker, 
Aitken and Lindblad (1956) using White Leghorns. They found 
that fertility declined as the length of the holding period in- 
creased, the rate of decline depending upon the holding tempera- 
ture. When stored at 30 degrees Centigrade, there was an im- 
mediate and rapid decrease in fertility. At 0 degrees Centigrade, 
high fertility levels were maintained for two hours but they 
dropped quickly thereafter. 
