Animal Breeding Intra-Uterine Influences
Animal Breeding Intra-Uterine Influences The relation between influences chiefly external in their origin and certain features of development abnormal in their character, has been affirmed and denied. These abnormal characters are generally apparent at birth, but when they are not physical in their character, they may not be noticed until sufficient time has elapsed to enable them to manifest themselves.
Observation has shown that in development in utero, certain results occasionally appear of such a character that it would seem reasonable to link them with certain occurrences, in the relation that result bears to cause. Others again claim that it is not necessary to link these occurrences with the external causes to which they are frequently attributed, since they may be otherwise accounted for.
Intra-Uterine Influences Defined. —Intrauterine influences in the broad sense of the term are those influences which affect development in the embryo, but in the present discussion only such of those are considered as in the main tend to produce abnormal characters. That abnormal peculiarities which cannot be recognized as family characters are occasionally observed in animals when they are born cannot be denied.
They occur not only in mammals where the relation between the mother and the embryo during the period of utero-gestation is both close and intimate, but also in fowls and reptiles where the egg is separated from the mother before there are any indications of embryological development.
Illustrations of Influences Affecting Intrauterine Development. —
- Within a few months after the violent cannonading and explosion of the arsenal which occurred at the siege of Landau, in 1793, Baron Percy states that ninety-two children were born in the district, fifty-nine of whom were still born, or died soon after birth, or were possessed of abnormal peculiarities. These results have been assigned to the alarm caused by the influences referred to and the natural results therefrom upon the organization of the mothers who bore the children. Two of them were born with numerous fractures of the bones and limbs.
- The color of animals has frequently been influenced by that of external objects presented to the vision of the parent or parents at the time of conception. The relation between the influence and the results named had evidently, been noticed at a very early period. So, well was this relation understood in the days of the patriarch Jacob, that he was enabled to utilize the knowledge in a way that greatly enhanced his wealth, as recorded in Gen. xxx. 25-43.
The knowledge of this relation has also been turned to good account in practical breeding, as when, for instance, colts have been sought from a valuable stallion but possessed of an undesirable color. In many cases colts of pleasing colors have been obtained by introducing an animal before the vision of the mother at the time of conception, which possessed the color or colors desired.
- Deformed children have frequently been produced by mothers whose attention has been strikingly arrested while the said children were in process of development in the uterus, by objects possessed of deformity more or less similar to those which have characterized the children. These, it has been noticed, are more liable to occur when the pregnant mother has been suddenly startled or affrighted by some sight or sound that has made a vivid impression on the mind.
So frequent are those instances and so prevalent is the belief as to their cause, that mothers are oftentimes careful to warn their pregnant daughters to avoid, when possible, the sight of objects that are calculated to produce impressions that are disagreeable or repulsive, and more especially during their first pregnancy.
These results have also been traced to causes which were operative sometime before conception. Dr. Allen Thompson, as quoted by Miles, cites the case of a woman, who six weeks before conception was suddenly affrighted by a beggar who had a wooden leg and who also presented a stumped arm as he threatened to embrace her. The next child had two stump arms and one stump leg.
Peculiarities have also characterized individuals which would seem to be the outcome of the habitual mental condition of the mother.
In Minneapolis, in 1895, a woman was on exhibition who had a long and flowing beard. She was married and had borne children, which, however, had died young. She was gentle and ladylike in manner. In conversation with a young physician who accompanied the author, she accounted for the beard by saying that her mother had been passionately fond of looking at the pictures of men with handsome beards.
But the most remarkable instance on record of what would seem to be the influence of the perceptive powers on intra-uterine development occurred at Maysville, Kentucky, in the year 1864.
- In that year a Jersey heifer owned by John B. Poyntz, produced a calf with the letters U. S. distinct- ly traceable on the left shoulder. The heifer was reddish or fawn in color, and the letters were distinctly traceable in the white hairs that composed them. This heifer along with others of the same breed was being pastured in a wood lot simultaneously with some twenty to thirty horses belonging to the United States government, each one of which on the left shoulder bore the brand of the letters U. S.
The heifer in time produced a calf with similar markings, except that the S was not so distinct as in the dam. Sworn statements to these facts were secured by Dr. Miles in 1875 from John B. Poyntz and others personally cognizant of these facts.
Two Theories as to the Cause of Intra-Uterine Peculiarities. —Two theories have been advanced as to the cause of abnormal peculiarities in the development of the fetus. The first associates them with some mysterious influence exerted on the imagination of one or both parents at the time of conception, or with impressions violent or otherwise made upon the mental or emotional nature of the mother during the process of intra-uterine development.
These influences however are usually considered as applicable only to the female. The only influence of course that could possibly be attributed to the male would be that which affects the imagination, and it would not seem possible for it to exert any influence on the progeny subsequent to the time of mating, that is to say, it would seem absolutely impossible that any mental condition of the male subsequent to that period could have any influence on his progeny al- ready in process of development.
Whether the imagination of the male exerts any influence is a question not easily susceptible of demonstration. There should be little doubt, however, but that the habitual mental condition of the male does affect transmission in virtue of the first law of breeding, but whether any vivid conception that may possess the male at the time of mating or, but a brief time previously does affect the progeny, is not so apparent. The second theory attributes them to the operation of natural laws governing physiological and pathological conditions, nearly all of which are understood, and which interfere with the natural processes of development.
Reasons Sustaining the First Theory. —The following are the principal reasons advanced in support of the first theory:
- The instances are numerous in which the relation between the alleged causes of intra-uterine malformation and the results is both intimate and close. This has been shown in the illustrations given above, and as intimated, many more could be given equally strong in character. So direct does the relation seem to be in many of those instances that to deny such a relation in the absence of reasons positive in character which account for those peculiarities in some other way, would do violence to the claims of evidence positive in character over that which is negative.
- It is a fact that the arguments which would assign such malformations to other causes is chiefly of a negative character. This of course so far weakens their value as testimony. The chief of these will be given in the paragraph below.
- The correctness of the assumption has been utilized with advantage in breeding. This has al- ready been referred to when speaking of the possibility of obtaining desirable colors in the progeny by placing an animal possessed of such color before the vision of the female at the time of conception. It is not reasonable to suppose that such practices would have been resorted to had experience not shown that there was at least reasonable certainty in the results that were to be looked for.
Reasons Opposed to the First Theory. —The following are some of the objections urged against the first theory: 1. Malformations of the fetus often do not agree with the apprehensions, a priori, of pregnant mothers. For instance, in the human family pregnant mothers who have been greatly concerned lest they should bear malformed children be- cause of some sudden shock given to the system through fright or otherwise, have borne children quite free from any deformities.
Mothers who have borne one or more deformed children and who are apprehensive lest such deformity should again manifest itself in the offspring, frequently bear children subsequently that are perfectly healthy. The most that this objection would seem to prove would be, that the alleged causes of such deformity are not always operative.
- Malformations occur among the inferior animals in which the development of physical life is very imperfect and when oviparous generation would seem to preserve the young from the influence of disordered maternal imagination. Malformations occur with serpents and other inferior orders of animals when it would be scarcely possible to link the imagination with the malformation that occurs. In oviparous generation it would seem difficult to link any influence of the imagination of the mother with the generation of malformed progeny, since the latter are developed in embryo entirely apart from the mother.
The most, however, that such evidence proves, is, that all instances of malformation would not seem to be dependent on a disordered condition of the mind or nerves of the mother.
- When twins are born in the human family, one child may be well-formed and the other malformed. With domestic animals that produce two at a birth the same is sometimes true, and with those that produce more than two, some may be normally developed while others will be malformed. It would seem reasonable to suppose that any influence of the imagination that would cause malformation in one of the progenies would similarly affect others of the same birth.
But this idea must not be pressed too far, since where all the influences are normal, there is frequently a marked difference in the size, form and color of individuals in the progeny, and yet little is known as to why those differences exist.
- The more deeply situated organs, the existence of which may be unknown to the pregnant mother, are frequently malformed. For instance, the internal structure of the ear may be so malformed as to pro- duce deafness, and yet the mother may know nothing of the structure of that part of the organ of hearing, not apparent to the eye. This argument, however like the preceding, only proves that instances of malformation may occur from causes altogether separate from any influence that can be exerted by the imagination.
- The anatomical relations of the embryo and its uterine envelopes would seem to render it improbable that any mental impression of the mother can be made to affect any part of the fetus. The limitations of our knowledge, however, may only be thus rendered more apparent, since some instances of malformation seem to result so directly from the influence of the imagination that it would seem hazardous to separate the result from the alleged cause.
Reasons Sustaining the Second Theory. —The following are chief among the reasons given to support the view that natural causes furnish a sufficient explanation of the abnormal peculiarities which manifest themselves during the process of intra-uterine development: —
- In malformed births dissimilar parts are seldom fused into or united with each other. While the gullet sometimes fuses with the larynx, not being originally dissimilar but formed from a common mass, neither larynx nor gullet ever fuse for instance with the bladder or rectum.
- ~Ko malformed organ loses entirely its own character or determinate place, and no malformed animal loses its generic distinction. For instance, the malformed fore-leg is associated with the development of the fore quarter rather than with that of the intestines, and the malformed sheep never so far loses its identity as to be mistaken for the bovine species.
- Mature does not deviate ad infinitum, since even in monstrosities a distinct gradation and natural order are observable. These are observable, as Vrolik has shown,
(a) in the number or proportion in which they occur within a certain period of time ;
(b) in the sex;
(c) in the definite proportion between the species of animals and the more frequent monstrosities in them;
(d) in the constant form of monsters even among heterogeneous animals; and (e) in the greater predisposition to monstrosity among some animals.
From certain statistics compiled it has been found that one monster occurs in the human family in about 3,000 births. In females, malformations more frequently occur from impeded development and in males from what may be termed excessive development, but there are exceptions.
Monsters with one eye and which have a snout are more frequent in swine, and double monsters in man. Headless monsters and also other forms have the same characters in Mammalia as in birds. The occurrence of monsters is more frequent in the higher orders of animals, and it becomes less frequent as the scale descends.
According to the author quoted above, three fourths of the entire number of monsters occur among Mammalia and one fourth among birds. They are infrequent among reptiles and still less frequent among fish. They are also more frequent among domestic animals than among wild animals. These arguments tend to show that even the development of monsters is subject to fixed organic laws so far as the immediate cause is concerned.
This fact it has been argued would exclude the influence of paroxysmal causes. In the judgment of the author, such a conclusion is not necessary, since it fails to distinguish between what may be an original and an immediate or secondary cause.
The conclusion would seem to be legitimate that the greater frequency of monstrosities among the higher orders of animals tends to sustain the view that mind, when viewed as the original cause, does exercise an influence through paroxysmal conditions for which it is responsible, in the production of monsters.
Resemblance in Fetal Development in its Early Stages. — The fancied resemblance in the fetus in the human family to that in some of the lower animals may be explained in accordance with the known laws of embryological development. There is a close resemblance in the embryo of all vertebrated animals in the initial stages of development.
This arises from the fact that animal development is general at the first. As development progresses the more special features evolve themselves. Up to a certain stage of fetal development the order even to which the fetus belongs cannot be known from its characters.
But, with the progress of development, the order, the family, the genus, the species, the variety, the sex and the individual, gradually unfold themselves, and in the order named. It follows, therefore, that the earlier the cessation in development occurs, the closer is the resemblance likely to be between malformations in the human family and those in the lower orders of animals.
The Immediate Cause of Malformations. —Reference has already been made to the immediate or secondary, and original or first causes in the pro- duction of these phenomena. The latter influence is much better understood than the former. The immediate cause of the malformations under consideration is impaired nutrition of the embryo or of some of its parts. This may arise from any severe shock of the nervous system in the mother by fright or otherwise. But why these influences should thus affect nutrition, or how, is yet a mystery.
The dependence of the immediate cause, however, on the primary cause, would seem to be so clear as not to be gainsaid. The habitual mental condition of the mother may also tend to arrest development by impairing nutrition.
This influence is better understood when the habit of the pregnant mother in the human family is continually sorrowful, the vital energies are lowered, in consequence of which the fetus suffers in common with all parts of the system. But this influence may be operative and yet it may not produce any form of malformation.
In fact, it may be questioned whether malformations ever result from this cause alone. The extent of the malformation is largely owing to the stage of pregnancy when the development of the deformed organ or organs begins. The earlier that it occurs the greater the deformity will be since the individual parts are then less distinctly evolved.
Obscurity That Yet Veils the Subject. —The explanations given throw some light on the causes of these phenomena, but they do not satisfactorily account for all classes of abnormal peculiarities. Some of these appear to arise from influences which act upon the imagination, and which are not paroxysmal in character.
Such are color markings and, in some instances, possibly even certain peculiarities of form. The relation between the influence of the imagination that is not paroxysmal in character and the results, is even more mysterious than those results which appear to come from paroxysmal influences.
In the present state of our knowledge the whole question may be thus summarized:
- The immediate cause of malformations is arrested development
- But many, at least, of those instances of arrested development would appear to be in some way dependent on original or primary causes such as strong mental impressions made on the mind of the mother at or shortly before conception, and paroxysmal influences such as arise from sudden fright.
- The way however in which those influences tend to produce arrested development is not clearly understood.
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