Hood, E. Carleton

English

Northwestern University Illinois, School of Law: Scholarly Commons

Journal of Criminal Law and CriminologyVolume 24Issue 5 January-February Article 13Winter 1934Microscope and Photomicrography in CriminalInvestigation, TheE. Carleton HoodFollow this and additional works at: https://scholarlycommons.law.northwestern.edu/jclcPart of the Criminal Law Commons, Criminology Commons, and the Criminology and CriminalJustice CommonsThis Criminology is brought to you for free and open access by Northwestern University School of Law Scholarly Commons. It has been accepted forinclusion in Journal of Criminal Law and Criminology by an authorized editor of Northwestern University School of Law Scholarly Commons.Recommended CitationE. Carleton Hood, Microscope and Photomicrography in Criminal Investigation, The, 24 Am. Inst. Crim. L. & Criminology 1004(1933-1934)THE MICROSCOPE AND PHOTOMICROGRAPHYIN CRIMINAL INVESTIGATIONE. CARLETON Hooui 'Every day we hear of new discoveries, all tending to make crimemore and more unprofitable. It used to be the fashion to believe thatthe police and detective methods of France were more efficient thanour own. But it is difficult to compare the criminal problems of thetwo countries, and therefore the methods employed by their police.It is my own view that the systems of both countries are extraordi-narily efficient. This in no way alters the fact that France makesgreater use of scientific men in connection with criminal investiga-tions. Experts are employed extensively in this country, but theyare not officially attached to the police. It is our want of organizationand not our use of science which is at fault. The policeman doesnot understand the scientific man, nor the scientific man the police-man. Nor will they ever understand each other until they worktogether.With these considerations in mind this paper is written. Init I endeavor to show that the scientific man is not always shut upin his laboratory for the purpose of working out abstruse problemsin mathematical physics or physical chemistry quite incomprehensibleto average men and women. He is, on occasion, capable of beingpractical and presenting his dicoveries in an intelligible way. Thatis a point of view likely to be received sympathetically both by thepolice and the public which science, in an unobtrusive way, does agood deal to serve.It is, from first to last, the practical test which is supreme.Most of us remember the scorn in which the official police aresupposed to have held Sherlock Holmes with his lens and his theories,but however much they may have resented the infallibility of hisdeductions, they came at last to recognize the value of his lens. Butprejudice dies hard. It is only comparatively recently that the uses ofthe microscope for every-day purposes have been recognized as some-thing to be employed not noly in specialized and expert investigations,but simply an instrument whose essential function is to magnify.'Research Assistant, Scientific Crime Detection Laboratory, NorthwesternUniversity, Chicago.[1004]POLICE SCIENCE 1005Yet its value to the police was proven many years ago. There was thestabbing affair in which no other clue was available except a knife,upon the blade of which appeared a few letters which the naked'eye could not read. The microscope, however, revealed their iden-tity. A careful and painstaking investigation traced the weapon onthis slight clue, to the woman who had originally supplied it to themurderer. He was arrested and, on confirmatory evidence, convicted.There was nothing more than those four letters by which totracehim, and these would never have been deciphered but for the micro-scope.An example such as this widens the sphere of the microscopeat once. It emerges from the august seclusion of the laboratoryand becomes, as it were, the most approachable of all scientific in-struments. Because, up to a point, it can be used by anyone. Thehigher branches of microscopy are among the most specialized inthe world, but the instrument nevertheless has familiar uses forthe amateur. Unlike chemistry, which is a highly dangerous pastimefor the unintiated, microscopy can be use on occasion with profit bythose without scientific knowledge. The case quoted is one in point.The function of the microscope here was merely to magnify a fewletters unrecognizable by other means. An operator without scientificattainments would have been able to master the technique in a shorttime. This is not to say that all microscopy is in this category. Em-phatically it is not. The microscope recognition of starches andfibers, a comparatively elementary matter, cannot be undertakenexcept by an experienced investigator. It is not merely a case oflooking at something enlarged, but recognizing and identifying anobject the appearance of which to the naked eye and when greatlymagnified, is vastly different.There was once an expert who did not clealy recognize thisadmittedly nice point. He took his microscope into court with himand adjusted it for his own vision, then invited the judge to lookthrough it. His honor accepted the invitation, looked, saw nothingand said so. He naturally drew the conclusion, which happened tobe the wrong one, that there was nothing worth considering in theexpert's evidence, and found accordingly.Such a mistake is not made today. It is one of the principaladvantages of the microscope that, combined with the camera, it canproduce pictures available for demonstration in court. It is superiorin this respect even to chemical evidence. It is not usual to performexperiments in court, although this has occasionally been done. Thelo0 POLICE SCIENCErecord of the chemist is his notebook and his verifiable facts. Hecannot, as a rule, bring his test-tube and chemicals with him. Evenif he does, the significance of the experiments performed may belost upon the spectators. It is for this reason that the chemistgenerally makes a study of microscopy. He is thus able to combinethe technique of chemistry and the microscope and to express hismost important results in terms of illustration.Fibers have a characteristic form under the microscope by whichthey can readily be distinguished by the expert. Cotton differs fromlinen, hemp from manila, jute from esparto and so on. The typeof paper used in a forgery cannot be hidden from the eye of themicroscope.We are now in a region where only the expert can freely move.Magnification readily causes objects to assume quite different appear-ances. An ink stroke remains recognizable as an ink stroke. Itmerely looks larger than before. It is quite another matter to dis-tinguish fibers in their characteristic microscopic forms, when greatlyenlarged.This, however, is one of the most important developments ofchemistry and microscopy combined. That is why it has come aboutthat specks of dust, minute smears and stains, tiny clues which wouldescape the unassisted eye, are made to yield their secrets.Micro-chemistry, as it is called, has been for many years a re-cognized science but it is but recently that it has become an organ-ized branch of chemical technique. The chemist relies upon reactionswhich he can watch in order to detect the existence of a particularsubstance,--a precipitate of a peculiar color,--a dark stain in a smalltube,--the formation of a tinted solution when that of a suspectedsubstance is tested with certain chemicals. If he has not a sufficiencyof material, these things cannot be observed with the naked eye, butif the reactions are watched under the microscope, tests can literallybe applied to specks of dust and to minute droplets.This is only one branch of micro-analysis. In others the micro-scope need not be used at all. The methods employed in such casesare too technical to be of general interest. They rely, however, uponthe use of instruments of really marvelous precision for weighing andmeasuring. Here is a good illustration. The balance, an apparatusfor weighing used by the chemist for his every-day work, is sodelicate that if a piece of paper is weighed upon it and a small pencil-mark is then made on that paper, the graphite deposit producedby the pencil-point will add enough weight to unbalance the scale!POLICE SCIENCE 1007Imagine, then, the micro-balance, a piece of apparatus about athousand times more delicate than this, and you will have some con-ception of the accuracy of the instruments employed for micro-analysis.The importance of these refinements is obvious. It means notonly greater general precision, but it also makes possible the accurateexamination of substances when only minute quantities are avail-able. One of the difficulties of old-fashioned chemistry was thatunless a relatively large quantity of the suspected material was athand, useful conclusions often could not be arrived at. Micro-chemistry makes things very difficult for the criminal. He wil haveto remove traces of his presence and identity which he himself can-not see.It will now be evident that the examination of the wax in aman's ears to determine his occupation, although a delicate operation,has nothing of the mysterious in it. You remove the wax, dissolve it,and recover the substances you require to examine by variousmethods. It may be wheat starch; the microscope will infalliblypick that out for you, or a crystal of a characteristic shape whichreveals its identity, or a trace of aniline dye giving itself away bythe intense coloration that even a microscopic fragment will producein a drop of water. All the time the microscope is the chemist's ally.Beneath it, the reactions which show things for what they are,-reactions between drops and specks, take on the appearance of large-scale operations.From the detection of the deadly atropine used by Dr. Eustachy,to the examination of the traces of dusts to be found in a worker'sears and which remain with him for many years; for the detectionof traces of everything from the rarest to the commonest, the micro-scope holds an enviable record in the solution of crime.Had its uses been unknown many murderers might have gone free.To mention an obscure example, it supplied the clue of the dandelionseed in the case of the French tramp; its evidence was the final linkcompleting the chain in the Gutteridge murder committed by Browneand Kennedy. Its powers are great, because their application ispractically unlimited.Most sciences have only a restricted application; all of themmust, in the last analysis, fall back upon microscopy. Microscopicmethods are essentially simple, and the evidence they supply can beappreciated by anyone. The judge and jury may not be able to recog-nize potato starch under the microscope. But there is always the1008 POLICE SCIENCEmethod of comparison, showing a photomicrograph of known potatostarch, and one of the suspected substance, and demonstrating thecharacteristics common to both. Seeing is believing. Comparison andcontrast are the basis of our judgments whether we are expert wit-nesses or one of twelve good men and true.We may as well emphasize that, in this connection, the scientificman differs not at all from the man in the street. For him also, onlyseeing is believing. In cases of crime, as in most other things, finetheories are of no use except so far as they help to establish a proofthat can be demonstrated as incontrovertible to those who did not in-vent it originally-probably could not have invented it, and thereforecould not be biased in its favor.

Microscope and Photomicrography in Criminal Investigation, The

https://scholarlycommons.law.northwestern.edu/cgi/viewcontent.cgi?article=2439&amp;context=jclc

Microscope and Photomicrography in Criminal Investigation, The

Abstract

Similar works

Full text

Available Versions

Northwestern University Illinois, School of Law: Scholarly Commons