THE MAMMALIA— MAN AND BEASTS. 
81 
.inimaux qui, dans Tctat ordinaire, ont la verge dirigec cn arriere, commo les Rhin- 
oceros, les Chameaux, les Lamas, Ics Dromadaires, etc., s’accouploieut cn arriere; 
mais il n’en cst rien; dans I'ercction, leur verge reprend sa direction en avant, ct lo 
coit a lieu comme a Tordinairc, mais, a la verite, avec plus de diflBcultc. Les singes 
sculs s’accoupknt d la mani^sre de Thorame, mais e’est a tort qu’on a pretendu quo 
Telephant cn faisoit de meme, Selon BuiTon, Ic male ct la femcllc du herisson ne 
peuvent s’accouplor comme les autros quadrupedcs ; il faut qu’ils soient face k face, 
debout ou couches. Les rats s’accouplent eu se mettant debout, votitre contre ventre. 
Dans bcauooup d'espcces chez lesqucllos, comme les chats, les lions, les gerboises, 
etc., Ic gland du male est muni do pointes cornecs plus ou moins longues, ct quelque- 
fois dirigecs en arriere, I’accouplomcnt est tros-doulourcux. Choz les chiens il dure 
fort long-temps, ce qui cst dd a une conformation particuliere du vagIn de la femelle. 
Dans d’autres, comme dans I’especc du taureau, il est terminc en quelqucs secondes. 
Tantdt la femelle se tient debout, tantdt clle s’accroupit sur ' ses deux jambes 
anterieures ; tantdt lo male se maintiont i Taide do scs deux memos membres 
dc devant, ou saisit la peau du cou de la femelle avec ses dents, etc. On a cru 
iong-teinps qu’un sixi^me ongle sumumeraire, qui se trouve au cote interne des 
pieds dc derriere des Eebidnes et des Oriiithor*hinqucs etoit destine a faciliter Tac- 
o.ouplement j mais ou a decouvert depuis peu quo cos organcs avoient un tout autre 
objet, et quo e’etoient des armes empoisonnees dont ces animaiix so servoient contre 
leurs ennemis; et e'est ce quo M. de Blainville a confirme. (Desmarest in Npuv. 
Diet, des Sciences Nat.) 
In some species of domesticated animals, especially in the Dog, copulation is main- 
tained for a long time after the omission of the fecundating fluid ; whilst among the 
greater part of the Birds, especially in the GaUinfic, the union is instantaneously dis- 
solved. It is always dangerous in the former cases to force a separation, which is 
sometimes attempted, although opposed by the peculiar organization of the sexual 
organs ; the intention of Nature apparently being, by this extraordinary prolongation 
of the union, to render conception more certain. LY'troito conjonction paroit 
destiuee, dans Ic principe, a produire i’irritation necessaire h rbmission de la semence; 
et le plaisir qui en resulte cst lo ressort qui determine lo plus puissamnicnt les anirnaux 
a la propagation, quoiqu’elle paroisse douloureuso d’abord dans quelques especes, 
eomrac dans lo genre chat, dont les femelles poussent souvent alors des cris aigus. 
Dans quelqucs oiseatix polygames aussi, comme les FaLsans, raccouplcraent paroit 
otro un actc plus violent que voluptueux ; car on voit les femelles redouter I’approclie 
du male, qui fait usage <ie sa force pour les y contraindre.^' (Yvart.) 
The older females of each species exhibit an attachment for the males, at an earlier 
season of the year than those of a less atlvanced age. After conception, a.s has al- 
ready been observed, the females, in general, repel the approaches of the male. In 
all coses where tho races are peculiarly ferocious, as in the Lion, Tiger, Panther, 
and other largo Cats, the females are the first to solicit tlic approaches of the male. 
Had this not been the case, it is difliuult to conceive in what manner their races 
could have been continued. In species of a milder disposition, the males endeavour 
fo please the other sex, and often exhibit a strongly-marked feeling of jealousy towards 
their own. The Monkeys remain attached to one or two females, rarely to more. 
Their union scorns to be a kind of marriage ; they require fidelity, are exceedingly 
jealous, and severely punish their female companions, who aro well-disposed to 
coquetry, on finding them in company with otlier males. 
Tlic phenomena of generation must, however, be considered in another point of 
view, at once singular and surprising. It seems now beyond a doubt, that the power 
^’njoyed by male animals of continuing their species depends upon the presence in the 
spermatic fluid of a certain kind of animalcules, which have thence received the name 
of Zoospermato* The testicle, or secreting organ, is well known to be the means by 
'vhich tho ovai’ia are fecundated ; and it is remarkable, that within this organ alone 
^oospcrniata have been hitherto observed. 
All animals, before arriving at the age of puberty, aro incapable of reproduction, 
and they are accordingly wholly destitute of Zoospormata. I\L Dumas informs us 
that he has made a considerable number of experiments upon young animals, and that 
he found all of them to be destitute of Zoospermata. He particularizes the young of 
fho Rabbit, Calves, Foals, young Asses, Guinea-pigs only a few months old, Mice of 
the same age, a great number of Norwegian Rats, with Pullets, young Ducks, and 
Gven Frogs. The fluid extracted from their organs contained the same kind of irre- 
i^ular globules which are found in tho testicles of the Mule ; but it was w'holly de- 
prived of moving bodies, and nothing was found wtiich could in any way approach to 
fhe peculiar form of those animalcules proper to fertile animals. 
It is well known that unitnaU become sterile at a certain period of life, varying 
'vith the species. To ascertain whether the presence of these anima!culc.s is essential to 
fecundity, it becomes necessary to investigate whether very old animals possess them or 
Hot, This, to a certain extent, has been done. M. Dumas exaniincd a Stallion 
®o<Jd twenty-five years, and which had been incapacitated through ago for about four 
or five years, as well as some Dogs of a very advanced period of life. Their sexual 
'“''gons Were perfectly licalUiy, yet he found them to be destitute of animalcules, and 
he fluid within them resembled in every respect that of tho young individuals already 
Mentioned. 
I'hesft facts serve to establish the importance of animalcules, and appear to show 
*-hcir presence is essential to the fecundating power of animals. 
^th the view of setting this interesting point beyond a doubt, many experiments 
been instituteil. The spermatic fluid of a Dog was placed in two silver capsules 
Hi equal quantities. In one of these, a metaUic rod, polUhed at its extremity, was 
Huged, III such a manner, that the rod and capsule might be placed in comnmiiic.i- 
011 with tile two surfaces of a Leyden phial, strongly charged. An electric spark 
llion made to pjiss through tho fluid, but not at its surface. After a few dis- 
had^^^** animalcules became entirely motionless, while tho other capsule, which 
not been electrified, was animated with them as cohipletely as it had been pre- 
mu 5 ly tQ exporiments, which did not last for five minutes, 
to ° of this and other experiments, which cannot bo detailed hero, appear 
j those animals possess irritability, and are destitute of the muscular 
ys cm of other animals. It is, however, certain that all male animals hitherto ex- 
amined, possess spermatic anirrialcules wlicn in a state of puberty. Young indivi . 
duals, as well as those that are aged, exhibit no traces of them, and even it is re- 
marked, that Birds are destitute of spermatic animalcules, except at those particulai* 
periods of the year w’hich Nature has fixed for their procreation. The domestic 
Cock and Pigeon, being fertile all the year round, are, of course, exceptions. 
These spermatic animalcules exist within the testicle in a state of complete pcrfec- 
tiou; they are transmitted to the deferential canals, without undergoing any altera- 
tion daring the transition. Neither their motion nor their form is influenced by the 
mixture of fluids from the other glands, so that, on being emitted, they appear in th^* 
same state as when in the spermatic vessels themselves. The spontaneous movement: 
of the animalcules is intimately connected with the physiological state of the indivi- 
dual which supplies them. Each species possesses a spedes of animalcule, of a form 
peculiar to itsdf, and no two species hitherto examined have the same kind of ani- 
malcules, although they always remain the same in the same species. The electri(‘, 
spark kills them, hut they an* not ntfcctcd by the galvanic current, even when u<ed 
in a degree of intensity sufficient to decompose water and the salts which it contains. 
Whatever opinion may be held as to the part performed by these animalcules, in 
the function of generation, it cannot be doubted that they exist solely in the essential 
pai't of the generative organ, in all animals which do not reproduce by buds or off- 
shoots. On the other hand, they are wholly wanting in animals incapable of gene- 
ration, and their presence in the seminal fluid may thence be assumed as the index of 
its fecundating power. 
With the exception of a few solitary instances of superfetation, it is always found 
among the ^Mammalia, that the fecundation of tliemale refers only to one birth, being 
that which next immediately follows tlic union of the sexes. On the contrary, with 
the Birds, a single imiou may influence several successive broods. Thus, the domestic 
Fowl will produce fertile eggs at tolerably remote periods of time, after having once 
received the influence of the male. A young and vigorous Cock is adequate for fifteen 
fowls, and serves to focundato all tho eggs they may produce during twenty days. Hence 
one male may be sufficient to give existence in a single day to three hundred chickens. 
The phenomenon of gestation can only bo observed in the Mammalia and 
other viviparous animals. Tlie term Gentation^ from the Latin yestare, to carry, 
denotes the period of time w'hich elapses between conception and birth. Among 
Birds and all other oviparous animals, a real gestation cannot exist, because the eggs 
det4ich themselves from the ovaries, pass along the oviducts, and ai'c deposited «as soon 
as they are formed. With these animals, gestation becomes superseded in general by 
incubation, to which it is greatly analogous, and the former function may thus be 
considered as little else than an internal incubation. The apparent design of Nature, 
in both coses, is to favour the gradual development of the embryo or foetus — the 
first rudiment of the now animal resulting from conception. It is also observed, that 
the rapidity of growtii in the foetus, whether during tho gestation of the viviparous 
animals, or the incubation of the oviparous, always diminishes in proportion as the 
fcBtus approaches the time ajipointed by Nature for its birth. 
Tho length of the period of gestation, like that of incubation, varies greatly among 
the several genera and species. It further obtains certain accidental variations, which 
appear to depend upon the age of the mother, her state of health, an increase or 
diminution in the velocity of the circulation, the quantity or quality of the food, and all 
those causes, derived from the influence of climate, soil, shelter, and the different kinds cf 
treatment which these animals receive from Man. The period of gestation may also 
be either shortened or prolonged, according to the temperature which prevails during 
that interval. It is a matter of common observation among graziers, that two cows, 
though fecundated on the same day, ^Yill yet produce at an interval of several weeks. 
The variation among sheep under similar circumstances amounts to a few days, but 
in general, this difference among domestic animals of ihe same species may extend as^ 
far as twenty days. 
It commonly happens in all those species, where the individuals take a long time in 
arriving at their foil growth, that the period of gestation is considerably prolonged ; and 
the converse ia equally true ; for in all those species which are very precocious, the time 
of gestation is extremely short. This rule is not, however, without many exceptions, 
llius, the Goat and Sheep are capable of reproducing at the ageof two years, and have 
commonly attained their full growth at this period, while their ordinary time of ges- 
tation is about'iivc months. On the other hand, a Lioness at the Menagerie dn Museum, 
in 1801 and 1602, seemed unfit for procreation before the ago of two years, and yet 
she produced after a gestation of 108 days only, or rather more than three months 
anjl a half. 
The duration of gestation seems further to depend upon the comparative volume 
of the species ; this rule, however, is by no means invariably preserved. Thus, tho 
Ass and Zebra, thougli less in volume than tho Cow and Buffalo, employ less time 
iu performing this function than the latter species. 
It hence appears that the duration of gestation varies in different animals, and the 
empirical laws deduced from multiplied observations are nut without many exceptions. 
By combining, however, tho general organization of the Mammalia, with the time ne- 
cessary for each animal to arrive at its full growth, as well as with the comparative bulk 
of the females, it is possible to obtain .a general and definite result ; while the charac- 
teristic thus obtained may, with propriety, be added to those which commonly serve 
to distinguish the leading groups of Mammalia. Thus in Man, nine months is the 
well-known period of gestation. Among the Quadrumana, it is also nine months for 
tho larger species, but only seven for the smaller. In the Carnassiers, gestation en- 
dures six months with the Bear; 106 days with the Lion; nine weeks with the 
Arctic Fox (Conw lagopus)\ from 55 lo 56 days with the Cat; the same period 
for the Martens and Weasels ; from 62 to 63 days with the Dog; and nine months 
with tho Morse. Those Mammalia which exporieuno the shortest term of gestation 
are unquestionably the animals belonging to the Order I\Lirsupialia. Among the 
large Kangaroos, for example, the young are scarcely more than an inch in length, 
when they first attach ihemsolves to the breasts of their mother, although the full- 
grown animal is at least five feet in height. Gestation U also of short dur.ation in 
the Rodentia, being only four months in the Beaver, one of the largest animals of 
this order. It U still less in tho smaller Rodentia, being from 30 to 40 days in the 
