Human Hair Studies: General Considerations of Hair Individualization and Its Forensic Importance Paul L

Journal of Criminal Law and Criminology Volume 31 Article 12 Issue 4 November-December Winter 1940 Human Hair Studies: General Considerations of Hair Individualization and Its Forensic Importance Paul L. Kirk Follow this and additional works at: https://scholarlycommons.law.northwestern.edu/jclc Part of the Criminal Law Commons, Criminology Commons, and the Criminology and Criminal Justice Commons Recommended Citation Paul L. Kirk, Human Hair Studies: General Considerations of Hair Individualization and Its Forensic Importance, 31 Am. Inst. Crim. L. & Criminology 486 (1940-1941) This Criminology is brought to you for free and open access by Northwestern University School of Law Scholarly Commons. It has been accepted for inclusion in Journal of Criminal Law and Criminology by an authorized editor of Northwestern University School of Law Scholarly Commons. HUMAN HAIR STUDIES* 1. General Considerations of Hair Individualization and Its Forensic Importance Paul L. Kirkt Human hair unquestionably figures whether a suspected hair belongs to a as a clue or possible clue in a very con- particular person is rarely carried fur- siderable percentage of crimes, particu- ther than to observe its most obvious larly those of violence, but only slight- properties, such as its color and its ly less in crimes of stealth, since most length, points which are obviously of individuals have a greater or less tend- very limited value. This is even more ency to lose hairs unconsciously and surprising when most criminal investi- at random. It is indeed strange that so gators are well aware of the possibili- tempting a type of evidence should ties of distinguishing the animal species have been so indifferently treated by of the hair, and spare no pains in en- criminal investigators. Some criminol- larging, sectioning, and otherwise in- ogists have expressed confidence in vestigating the hair from this stand- their ability to determine the source of point. This phase of hair study has un- a hair, but usually without benefit of doubtedly been inspired by such ex- adequate study and by methods that cellent investigations as those of Glais- are not generally known. The common ter (2), Hausman, (3) and others. attitude is well expressed by Sydney Some investigators (1, 4) go further Smith (1) who states, "If a definite and claim to determine age of human answer is required as to whether a cer- hair by such methods as measuring the tain sample of hair is that of a certain rate of solution of a hair root in caus- individual, the investigator is strongly tic potash. It would seem at least as advised to refuse to go further than to difficult to accurately determine the age state that the hairs are similar". With- as to determine the individuality of the out question, present knowledge justi- hair, if there is any analogy to other fies such a statement to a very consid- bodily structures such as friction erable -extent, but to accept this view ridges, or the physiogomy. fatalistically as the last word on the While thorough studies of the indi- subject is as strange as the attitude vidualization of human hair have not taken by many toward fingerprints in been reported, the total amount of hair the early days of development of that investigation which has been published important branch of criminological is very impressive. Without attempting knowledge. To the best of the author's to completely review the literature, information, the investigation as to some of the more recent and outstand- * These studies were made with the aid of a Works Progress Administration. grant from the Research Board of the University t Associate Professor of Biochemistry, Uni- of California, and of clerical assistance from the versity of California. [ 486 ] HUMAN HAIR STUDIES ing contributions are here listed. Haus- tors which may be significant in deter- man (3) has contributed an extensive mining individuality. series of papers on this subject, chiefly Early results of these studies appear from the anthropological point of view. to point very definitely to the possibil- Trotter (5) has made valuable sys- ity of making such identifications with tematic studies on human hair and has a very considerable degree of proba- reviewed the classification of hair (6) bility. It has, for example, been cus- quite thoroughly, along with an .excel- tomary for some years to require all lent bibliography. Another recent study students of criminological science in of classification was made by Eddy (7). the author's laboratory to identify a Methods of examination of hair have single hair from one of twenty samples, been discussed by Roig (8), Harvey all of similar color and from individ- (9), Fiale (10), Bellamy (11) and uals of similar age. To the present, no others. General discussions of the for- such student who has completed the ensic importance of hair and its study routine examination has failed to re- are included in most books on crim- port the identification correctly. While inology and forensic medicine, includ- this falls far short of placing a hair on ing Smith and Glaister (12), Soderman a single member of the world's popu- lation, it must be remembered and O'Connell (13), Smith (1), Dan- (a) that twenty suspects in a single crime is forth (14) and other similar references. rather an exceptional number; (b) Older work which has often been that the eliminative value of a failure quoted but is frequently inaccurate and to identify the hair as that of any of occasionally misleading is that of Lam- the suspect's is great; (c) that time bert and Balthazard (15). imposes on students a restriction on Since it is a matter of common obser- the total number of hairs that can be vation that an individual's hair is usu- examined, and it is impossible as yet ally more or less distinct in appearance to say whether they. could equally well from that of other individuals, it ap- pick, e.g. from 100 standards; (d) that peared well worth investigating to as- in any random group of suspects there certain if there are differences which would be greater normal variations are sufficiently fundamental and of than are present in the selected group sufficient magnitude to lend a reason- of similar hairs used for this exercise; able probability to an identification of and (e) that the students in question a person from one or more of his hairs. have never before examined hairs and In this series of papers it is hoped to are in no sense experts in this exam- report studies of various observable ination. and measurable differences of hair in In addition to the question of locat- sufficient numbers that statistical anal- ing from which of a number of hair ysis may be employed to determine the samples a single hair has been taken, exact variations of each of these fac- a considerable number of criminal PAUL L. KIRK cases involving human hair have been well. In order to make examinations investigated with results that are, to of hair, certain routine matters of say the least, gratifying. In one case, handling and preparation must be con- two fugitives from justice were located sidered. exclusively on the basis of a single hair If the bodily origin is definitely contained in the hat of one of them known it must naturally be recorded, which had been lost in flight. The iden- even to the extent of distinguishing be- tification in this case was later con- tween crown, nape and sideburns or firmed by fingerprints. In another case, temples of human head hair. Other hair believed to have come from the body hairs need not be considered here victim of an assault was located in the for they have not been studied to the lodgings of a suspect, while hair diag- extent of making individualization pos- nosed as that of the suspect was located sible as yet. Naturally it is necessary on the victim. The diagnosis was con- to be able to distinguish body hairs firmed by a plea of guilty. In another from head hairs, a matter which is case, the identification of the hair of a usually simple to the person who has suspect was confirmed by sufficient ad- had some experience in hair examina- ditional evidence of other types that a tion. It is as yet uncertain whether jury found the suspect guilty. In these hair from different portions of the head as in other cases, the individualization shows consistent differences which are of the hair has without exception been significant, but the distinction of areas confirmed when there were indepen- should be made until evidence is ob- dent means of obtaining confirmation. tained to settle the point. It would be imprudent to conclude The head hair is first examined with- that the procedure may for this reason out any cleaning or other treatment by be made infallible, but the results cer- placing it on a microscope slide, cover- tainly justify further studies so that as with a cover slip and examining it un- high a degree of probability as possible der magnification. At times there are may be attained in hair identification. particles of adherent matter which may At the very least, it is surely possible be significant. Ordinarily the debris is to develop the technique to the point merely a mixture of dandruff, oil, and of making it a valuable addition to common dust. After determining the criminological methods. importance of the debris, the hair is washed thoroughly in a mixture Technique of Examination of equal parts of ether and alcohol The total possible number of factors in a covered which might be studied in connection dish. This washing should be with human hair identification are very continued with agitation for about 15 large.

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