95 
July 26, 1842. 
William Yarrell, Esq., Vice-President, in the Chair. 
The following memoirs were read :— 
“Observations on the Semen and Seminal Tubes of Mammalia and 
Birds,” by George Gulliver, F.R.S. 
It has long been known that the testicles of Birds become much 
enlarged in the spring, and that the same organs of Mammalia are 
more or less increased in size at the rutting-season, and in young 
animals generally as they become capable of reproduction. Professor 
R. Wagner (‘ Physiology,’ translated by Willis, pp. 23 and 27) has 
noticed also the enlargement of the seminal tubes of all these animals 
at the periods above named; but as I am not aware that we possess 
any observations on this head svfticiently numerous and precise to 
be useful for reference and comparison, I am induced to submit to 
the Society a contribution towards this object, particularly as it ap- 
pears to me that the condition of the semen and testicles at different 
periods is an interesting inquiry in relation to the habits and economy 
of animals. 
During winter the coats of the seminal tubes of Birds are tolerably 
strong and thick. The increased size of the tubes at the season 
of procreation arises from the accumulation of semen within them, 
by which their coats are so much distended and attenuated that they 
are most easily ruptured, and are much thinner than the correspond- 
ing parts of Mammalia are at any time. 
In the following table the measurements are all expressed in vul- 
gar fractions of an English inch*, and where only one fraction is 
given it denotes the average size. With the exceptions dated No- 
vember and December, the animals were all examined during the 
present year, and, unless noted to the contrary, they were adults. 
In Birds the left testicle, which is commonly somewhat larger than 
the right, was generally the subject of observation. 
Table of Measurements of the Seminal Tubes, and of remarks on the 
state of the Semen and Testicles at different seasons. 
Date. Name of Animal. Size of Tubes. State of Testes, &c. 
— 
eb, — 4.|Maryeene2e | icisccccscss.+.c8ese0 1-142 to 1-77 |Scarcely any fluid in tes- 
tes. Died of pulmo- 
: nary consumption. 
Nia vO Ditto pat G" | .scuce sreededeaeh ome 1-150 to 1-78 |Died of chronic pericar- 
ditis. No spermatozoa. 
* [ take this opportunity of remarking, that all my microscopic measure- 
ments have been invariably given in vulgar fractions of an English inch, 
however they may have been set up in type for the sake of convenience. 
