SEXUAL ACTIVITY OF MALE RABBITS 469 
they will show reduced activity after continued stimulation. 
In fact, workers for the most part agree that reduced volumes of 
semen is one of the most regular concomitants of excessive sexual 
activity. 
Lewis (11, p. 30) recovered 65 cc. from a stallion on the 
first copulation of a test. This same stallion then made one 
copulation daily for nine days. On the ninth day only 5 ee. 
of semen were recovered. Again after the horse had rested 
nineteen days, 60 ec. of semen were recovered from a single 
copulation. 
Iwanoff (07, p. 494) found that the volume of semen ejected 
by stallions generally decreases with several copulations, but 
this decrease is variable. He reports one case of a stallion in 
which 33 cc. was discharged at the first copulation, 30 ce. on the 
second, and 28 cc. on the third copulation on the same day. 
The day following 20 ec. were dischargéd on the first copulation 
and 18 ce. on the third. On the third day there were 30 ce. on 
the first, 25 ec. on the second, but 40 ce on the fourth copu- 
lation. 
In a single observation reported by Lode (91) in man, the 
volume of semen decreased from 3000 cu.mm. on the first 
ejaculation to 2000 cu.mm. on the second copulation of the 
day. On the whole, how ver, Lode’s results are in remark- 
able contrast to those mentioned above. In the case of a 
dog the total volume recovered from the first ejaculation 
was 75. cu.mm. and on the fourth ejaculation of the day 1500 
cuumm. On a second observation, the volume of the first 
ejaculation was 800 cu.mm. and 1500 on the fourth (the length 
of the interval between these ejaculations is not stated). Lode 
makes much of this point; he quotes Ludwig (’91) as saying that 
‘“‘Man vermuthet, dass eine 6ftere Entleerung des Samen die 
Neubildung desselben beschleunige,’ and Nothnagel (791), 
‘‘Manches weist vielmehr darauf hin, dass nur nach vorherigen 
Entleerungen eine st°rkere Production stattfinde.”’ 
The volume of semen discharged by the male rabbit is neces- 
sarily very small, since the animal is small and the time of ejacu- 
lation is extremely short. We have found it impossible, as has 
