§ I. On Consanguinity according to Itself

I. Notion. Consanguinity is nearness between persons arising from this: that by carnal generation they descend either one from the other or jointly from the same proximate stock. It is called "proximate"; for remotely all human beings descend from one Adam or Noah, and yet for that reason they are not called consanguineous. Consanguinity is computed by lines and degrees (canon 96, § 1). Therefore, so that the definition handed down may be more fully developed, three things must be attended to in consanguinity: namely stock, line, and degree.

1. Stock is that person from whom others proceed as from a common proximate root. Commonly the stock consists of two persons, namely parents; sometimes of one person alone, namely if someone begot offspring from several persons.

2. Line is a series of persons descending from the same proximate stock. A twofold line is distinguished: direct and oblique.

The direct line is a series of persons of whom one proceeds from another, either immediately or mediately. It is called descending or ascending according as the series is numbered by descending from those begetting to those begotten, or by ascending from those begotten to those begetting.

The oblique line, transverse or collateral, is a series of persons who proceed from a common proximate stock, but not one from another, as brother and sister, maternal uncle and niece. It is distinguished into equal and unequal, according as two persons are distant from the common proximate stock by an equal degree or distance, as brother and sister, or by an unequal one, as maternal uncle and niece.

3. Degree is the measure of distance of one person from another. But degrees are computed thus:

a) In the direct line there are as many degrees as generations, or as many persons with the stock removed (canon 96, § 2). Thus, for example, a son is distant from his father by one degree, from his grandfather by two degrees. And both civil law and ecclesiastical law follow this mode of computing degrees in the direct line. Otherwise one must speak in the collateral line.

b) In the equal collateral line there are as many degrees as generations in one tract of the line, or there are as many degrees as persons in one tract, with the stock removed. Hence, for example, two brothers are consanguineous in the first degree, two first cousins in the second degree of the equal collateral line.

c) In the unequal collateral line there are as many degrees as generations in the longer tract, or as many degrees as persons in the longer tract, with the stock removed. Thus, for example, a maternal uncle and niece are consanguineous in the second degree of the unequal collateral line.¹ Degrees are computed according to the longer series because the reason of nearness and distance of collateral blood-relatives is taken from the fact that they are united in the common proximate stock. Hence they cannot be more united among themselves than they are united with the stock. But this would occur if the computation had to be made according to the shorter series.

But so that consanguinity may be perfectly exhibited, both the nearer and the more remote degree must be indicated. This is done, for example, if there is question of a maternal uncle and niece, by saying: they are consanguineous in the second degree mixed with the first, or touching the first.

Note. Civil laws which for the direct line follow the same mode of computing as ecclesiastical law, in the collateral line compute the generations of each tract, or the persons of each tract, with the stock removed. Hence, for example, two brothers are consanguineous in the second degree, two first cousins in the fourth, a maternal uncle and niece in the third degree. This mode of computing must be attended to when there is question of civil matter, for example, of the civil effects of marriage, as of hereditary succession.

II. Division. Consanguinity is divided:

1. Into legitimate and illegitimate, according as it arises from conjugal copula or from illicit intercourse. But since in each case there is a natural communion of blood, this division is not attended to in order to contracting marriage.

2. Into full and less full. The former exists among those who have father and mother as common stock; the latter among those who have only father or mother as common stock. The former are called full siblings; the latter consanguineous or uterine, according as father alone or mother alone is their common stock. But neither is this distinction attended to with regard to the impediment.

3. Into agnation and cognation, according as the communion of blood is transmitted through the masculine or feminine line. Those joined in the former way are called agnates; those joined in the latter way cognates.

4. Into simple and multiple. The former is had when two persons have only one common stock and ascend to the stock by only one way. The latter exists when each party has a double or multiple common stock, or each or one of the parties ascends to the same stock by a double or multiple way.

5. Into consanguinity of the direct line and of the oblique line, as was set forth on p. 637.

III. Mode of finding the degrees. The degree of consanguinity is found by making a genealogical tree. This is done thus: if the common stock is known, write that person's name on paper, then below him here and there the names of those descending from him through each line, until you arrive at the persons whose degree of consanguinity is being sought.

If the stock is unknown, first write the names of those whose consanguinity must be detected, then above the name of each put the names of the ascendants, until you arrive at the common stock. Let the schema be:

Benedict

1 Henry Mary 1 2 Robert Rose 2 3 Peter Jacoba 3

Peter and Jacoba are consanguineous in the third degree of the equal collateral line. Peter and Rose are in the third degree of the unequal collateral line, or - so that the consanguinity may be determined in every respect - in the third degree mixed with the second, or in the third degree touching the second.

¹ An unequal degree in the collateral line is called a mixed degree.

IV. Multiplication of consanguinity can occur in two ways: 1° by reason of the double or multiple way by which one or the other, or each, of the blood-relatives descends from one common stock; 2° by reason of a double or multiple common stock.

Three causes of multiplication are assigned:

1. The first cause of multiple consanguinity between two persons is that someone among their ascendants has offspring from a person consanguineous to himself. From this cause, indeed, multiple consanguinity can follow both in the first and in the second way: in the second, namely, insofar as besides the nearer common stock there is also another, more remote, common stock, to which one ascends without each line passing through the nearer common stock.¹

Let the schema for double consanguinity with one common stock be:

Peter

    1
    2 Luke

1 Rose 1 1 (1) Mark 1 1 (2) Andrew ........ X ........ Clara 2

3 Mary

         (3) Lucius 3

1, 1 Nilus

It is asked in what degree, by how manifold a consanguinity, and by what mode of multiplication Lucius and Mary are joined. From this schema it is evident that Andrew and Clara, that is, the father and mother of Lucius, were joined to each other in the second equal degree from the common stock Peter. But hence it happens that their son Lucius is bound with Mary in the third equal degree, not by a single consanguinity, but by a double one, yet not by a consanguinity of double stock but only of one common stock.

For double consanguinity with a double common stock from the same cause, let the schema be:

Mark

1 Luke

2 Mary

Jacob 1

.......... X .......... | 3 Peter (2)

2 Paul (1)

(1) Vincent 2 | (2) Flavia 3

It is asked in what degree, by how manifold a consanguinity, and by what mode of multiplication Peter and Flavia are joined. From this schema it is evident that Paul and Mary, namely the father and mother of Peter, were joined to each other in the second equal degree from the common stock Mark. Hence it happens that their son Peter is bound with Flavia in the third equal degree, insofar as Peter descends from the common stock Mark through Mary and Luke, while Flavia descends from him through Vincent and Jacob. Yet the same persons are at the same time joined in the second equal degree from the common stock Jacob, insofar as Peter descends from the common stock Jacob through his father Paul, while Flavia descends from him through Vincent. But since Peter ascends to the more remote stock Mark not only through the nearer common stock Jacob, but also by another way, through Mary and Luke, which does not pass through that nearer stock Jacob, therefore between Peter and Flavia there is a consanguinity of double stock.

The following causes always carry with them multiplication of consanguinity by reason of double or multiple stock.

2. The second cause is that persons consanguineous among themselves have begotten offspring from persons consanguineous among themselves. For example:

Anthony Charles

1 Lucretia ... X ... Paul 1 1 Peter ... X ... Mary 1

2 Jacob (2) (2) Flavia 2

3 Robert (3) (3) Magdalene 3

In this schema there are two brothers, Peter and Paul, who respectively contracted marriage with Mary and Lucretia, two sisters. Hence it happens that the descendants of each of those marriages are mutually doubly consanguineous, by reason of a double common stock: namely, by reason both of Anthony, who is their grandfather or great-grandfather on the father's or grandfather's side, and of Charles, who is their grandfather or great-grandfather on the mother's or grandmother's side. And thus Jacob and Flavia are consanguineous in a double second equal degree; Robert and Magdalene in a double third equal degree.

3. The third cause is that someone successively had offspring from several persons consanguineous among themselves. For example:

John

1 Mary ... X ... Peter ... X ... Anna 1 | | 2 Andrew (1) (1) Robert 2 | | 3 Rosalia (2) (2) Aloysius 3

In this schema John is the father of the sisters Mary and Anna, whom Peter successively knows, and from there the others descend. Therefore Rosalia and Aloysius are doubly consanguineous: first indeed in the second equal degree of the collateral line from the common stock Peter, and then also in the third equal degree of the collateral line from the common stock John.

V. The mode of detecting every consanguinity which exists between two persons is this: let a genealogy of each be made through all ascendants, both fathers and mothers, up to the third degree inclusive. Then apply these things:

1. Persons who occur in each genealogy constitute, individually, the common stock of those whose consanguinity is being sought. Note, however, that a common father and mother constitute one stock.

2. As often as the same person recurs in the same genealogy, so often is consanguinity multiplied, because by so many ways one ascends to that stock.

¹ Cf. Holy Office, March 11, 1896, and February 24, 1899 (Collectanea Brugenses, I, p. 376, and IV, p. 422 sq.).