Technical Consideration



The methods described are intended to record, either by printing with

ink or by photographing as legibly as possible, the ridge details of

the tips of the fingers of unknown dead for identification purposes.

The securing of the impressions enables the fingerprint examiner to

classify and search them through a file. This search, of course,

means merely to make a comparison of the deceased's prints with the

prints of known individuals.



It is well to bear in mind the fact that the dermis or epidermis may

have undergone certain physical changes and that in order for the

fingerprint examiner to make a proper comparison he must know the

changes which can and do occur. Otherwise, he may fail to make an

identification (fig. 403).





[Illustration: 403. Epidermis or outer layer of skin commencing to

peel from dermis or second layer of skin, result of decomposition.]



Consider first the epidermis or outer layer of skin in cases of

maceration (the skin is water soaked). There may be considerable

swelling. The ridges become broader and are more distinct. An inked

impression in such an instance may show a pattern larger in area than

a print made from the same finger when the person was alive. Also, if

the skin is on the finger but is loose, inking and rolling could

distort the impression so that some of the ridge formations would seem

to be in a different alignment from corresponding details in a print

made during life. When decomposition commences, what are really solid

ridges may be broken, giving rise to the possibility that there appear

to be more characteristics than there actually are (figs. 404 and

405).





[Illustration: 404. Inked fingerprint made during life.]



[Illustration: 405. Inked impression of same finger of deceased

showing effect of decomposition.]



The existence of wrinkles may also cause the impression to acquire an

appearance of dissimilarity when compared with the original inked

print.



With respect to cases of desiccation, there will probably be

shrinkage, hence, the impressions made may appear smaller than in life

and the ridges will be finer. In cases in which the epidermis has been

lost and there remains only the dermis or second layer, there will

usually be shrinkage with the same results. Here also, wrinkles, if

present, may cause a difference in appearance from the normal print.







In addition to shrinkage and wrinkles in cases involving the second

layer of skin, there is a radical change in the appearance of the

ridges themselves. The second or dermal layer of skin is composed of

what are called dermal papillae which have the appearance of minute

blunt pegs or nipples. The dermal papillae are arranged in double rows

(fig. 406). Each double row lies deep in a ridge of the surface or

epidermal layer and presents the same variations of ridge

characteristics as are on the outer layer of skin except that they are

double. Accordingly, when the second layer of skin is printed or

photographed, the ridge detail will appear in double. That is, the

ridges will appear as though they were split. This may well confuse

the fingerprint examiner in that what may be a loop having 10 ridge

counts may appear to be a loop having 20 ridge counts when the

impression is made from the second or dermal layer of skin. These

double rows of ridges are finer and not as sharp as the detail on the

outer skin, which adds to the difficulty of arriving at a correct

classification and making a proper comparison.





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