264 MR. NEWPORT ON THE IMPREGNATION OF THE OVUM IN THE AMPHIBIA 
of a mere vehicle for the ready transmission of the spermatozoon to the ova, and as 
allowing greater freedom of motion to these bodies. 
It is true, as Wagner and Leuckardt have stated, that but little motion can be 
observed in the spermatozoa of Insects when they are united into cords ; yet this 
seems to be due rather to their union into these masses, and to have reference to 
their mode of ejection from the body of the male, as in the Triton, and is known to 
take place during their collection in the deferential vessels, than to any real absence 
of a power of motion in them. This is not their condition when brought into contact 
with the egg at the time of impregnation. When the fluid of the male insect, during 
pairing, is passed into the sperrnatheca of the female, where it may be destined to 
remain Vor an indefinite time, the spermatozoa compose the chief portion of it, as in 
the Tritons; but, during their residence in the sperrnatheca, the spermatozoa are 
mixed with ’a fluid, which is supplied by a gland attached to that organ, and which 
becomes to them a vehicle like the liquor seminis, and allows of their separation and 
independent motion, and thus appears to answer the purpose of the true liquor 
seminis in the Mammalia. At the period when the ova are descending from the 
ovaries, the movements of the spermatozoa become more distinct ; and when these 
bodies ’are brought into contact with the egg, as it passes the outlet of the sperma- 
theca, they become more isolated, and their movements more intense, as I have seen 
in the case of the Orthoptera. From these circumstances I am led to believe that 
some degree of motion will ultimately be observed to mark the perfect condition of 
the impregnating agent in all animals. The facts already mentioned coincide with 
this view, and point to the probability that the degree of impregnating force in each 
individual may perhaps be indicated relatively by the degree or intensity of motion 
in the spermatozoon, and the duration of this force by the length of time which the 
spermatozoon continues in motion. 
The established fact, that a difference in the structural conformation of a body is 
the invariable result of a difference in the relations, proportions, and composition of 
its material constituents, has always afforded reason for presuming that some material 
influence may be transferred from the substance of the spermatozoon to the contents 
of the ovum, at the time of impregnation. The function of impregnation appears to 
be one of definite relations and proportions. Thus we have seen, when only a feu 
spermatozoa were applied to the ovum on the point of a pm, that full impregnation 
was but rarely effected. In most instances of such limited application, the yelk 
underwent only partial segmentation, and its changes were then gradually arrested, 
and no embryo was produced. If, however, the pin point which had been charged 
with spermatozoa, instead of being applied to the ovum for an instant only, was 
allowed to remain in contact with the egg for a second or two, and thus by capillarv 
attraction became drained of the spermatozoa which adhered to it, and, as a conse- 
quence, thus made to deposit a greater number of these bodies, which were not 
afterwards attempted to be removed or destroyed, then impregnation was sometimes 
