Break Frames | Home

42 Central Law Journal 323
April 17, 1896

    Chemical Experts—A Trio of Important Factors in the Detection of Crime.
    Percy Edwards

  1. As expert agencies in leading to the detection of a crime and in aiding the courts in meting out justice to offenders against the majesty of the law none are more important than chemistry; largely because of its scientific exactness. And this certainty of analysis aided by the power of the microscope, and the wonderful reproductive force of photography combined, have marked the destruction of many poor guilty wretches and such scenes as that court scene described by Dr. Holland in his story of Seven Oaks, are not, in the light of modern science, to be regarded as miraculous. The darkened court room; the awed silence of the assembly; the intense mental strain on those more deeply interested; the awful force of the blow to the guilty man when he first beholds the evidence of his crime illumined by the light of scientific test. Forgery detected by chemical analysis, is not of such rare occurrence in modern times. The murderer, intent on his effort to avoid suspicion, or to throw off the scent of pursuit already hot on his tracks, yet forgets the little spot, almost infinitesimal, caught somewhere on his clothing in the deadly struggle with his victim. He is in the meshes of the law at last. But even then he is secure in his own mind. He knows there was no eye-witness to his crime. He has closed all avenues to detection. The officers of the law have done all they can do. They have faithfully followed every available clue which presented any chance for a solution of the mystery, and now they are at their wits end. The prisoner clamors for his liberty. In our country, as in all other well governed countries, liberty is one of the dearest rights constitutionally guaranteed. It must not be abridged without due process of law. The prison doors are about to open for this guilty wretch when the smallest evidence of his guilt is found. The chemical expert determines the small dark spot on the man's clothing to be human blood. He is held for trial. How is it to be known whether this dark spot is human blood, or the blood of some animal of the brute creation. Chemical science aided by microscopical observation has determined that the fluid of the blood contains a large number of corpuscles. They are counted, measured and photographed. The difference in size, form and condition of these corpuscles in the different members of the animal kingdom is carefully noted. Although the average diameter of the human red corpuscle is still a matter of discussion, the best authorities place it somewhere between 1-3200ths and 1-3500th of an inch in both male and female. These human corpuscles then are to be compared to the corpuscles of the brute creation which chemical experts of great learning have determined to range from 1-3540ths of an inch in a dog, to 1-6366ths of an inch in a goat. Here then is the value of such agencies as science has produced. This evidence, although not infallably correct, is worthy of greatest consideration by court and jury as being of the best of opinion evidence. Beginning with this slight, but terrible indication of guilt, step by step the awful revelation follows, and the guilty one is brought at last through the employment of scientific agencies, to the bar of justice. It will not do to give in detail instances of causes celebres in which these agencies played an important part, in a paper of the length to which this is limited. In many cases an historical importance is given them. It is proposed in this paper to avoid any extended general detail or discussion of the subject, and merely to collect together the case law under these three divisions of the subject: 1. Evidence as affected by opinions of chemical analysis. 2. Evidence as affected by the opinions of microscopists. 3. Evidence as affected by the opinions of photographers and photographic copies.

  2. The practice of admitting the testimony of witnessess [sic] who have become qualified by application and experience to express opinions based upon special knowledge of the subject under inquiry is not of modern origin. Such persons as were by the Roman law artis periti were summoned into court at the discretion of the judge, so that he might have the advantage of their special knowledge. So the celebrated Criminal Code of the Emperor Charles V. contained an enactment requiring the opinion of medical experts to be taken in those cases when death was caused by violence. In the year 1553 Mr. Justice Saunders said in the case of Buckley v. Rice: 1 "If matters arise in our law which concern other sciences or faculties we commonly apply for the aid of that science or faculty which it concerns, which is an honorable and commendable thing in our law, for thereby it appears that we don't despise all other sciences but our own, but we approve of them, and encourage them as things worthy of commendation," and instances are recorded in the year books where the courts received the opinions of witnesses who were learned in special sciences and arts. The rule permitting this opinion evidence is exceptional. No rule is better known to trial lawyers than that the opinions of witnesses ordinarily are inadmissible. It is facts, hard, cold facts such as were the groundwork of the philosophy of Thomas Gradgrind, which witnesses are in most cases expected to give. It is not always necessary, that a witness should be an expert to give opinion evidence. But it is the province of the court to determine from surrounding circumstances whether or not he will receive other than the testimony of professional witnesses.

  3. Evidence as Affected by Opinions of Analytical Chemists.—In the detection of poisons by experts the courts receive great help in these days. In England in the year 1530 we are told the offense of poisoning was made high treason, and the offender was denied the benefit of clergy and boiled to death. This terrible form of punishment was largely due to the difficulty in those days of bringing to justice such an offender because of the crude methods of testing by chemical analysis to determine the presence of the poison in the human body. At the present time however all poisons known may be detected by modern methods or scientific test. It has been decided by the Massachusetts court that a chemist who has made an analysis may testily as to what he finds. 2 In these cases of poisoning a thorough chemical analysis of the contents of the stomach and bowles and other parts are deemed indispensable to a correct test for poison in the system. Symptoms of themselves without attendant circumstances are unreliable. 3 In cases of suspected poisoning, the chemical analysis should if possible be made by a chemist of undoubted repute and experience, then in such cases where the testimony of such experts is to be received as to the contents of the stomach, care should be taken to show that the particular anatomical specimen under examination has not been tampered with or any chance interference, and such proof will be exacted. 4 Physicians may give opinion evidence of this character as well as professional chemists. 5 In the examination of blood spots chemists and microscopists may give testimony as to the fact of it being the blood of a human being or that of the brute animal. Such evidence has been received in numerous cases, and now is received without objection. In all these cases the court should require that all questions pointed towards an expert opinion are properly predicated upon facts shown. In the case of State v. Knight, supra, the court uses this language: "It would be very difficult for an expert of the most accurate and extensive observation, to exhibit in language, with precision, so as to be understood, those delicate appearances which are appreciable only by the sense of vision. Nothing short of an exact representation of the sight can give with certainty a perfectly correct idea to the mind. A diagram approximating in any degree to perfect representation, when exhibited by one qualified from knowledge and experience to give explanation, may do much to make clear his testimony without [**325**] danger of misleading." And so enlarged photographic copies may be used to assist chemical and microscopical observation, and to preserve the results of such observation. Ordinary witnesses may testify as to blood stains. 7 But such testimony is liable to suffer in a comparison with the technical knowledge of an expert chemist. It would seem that the ordinary witness testifying as to blood stains is not expected to state more than as to the mere fact of such spots being blood spots. He is not expected to give technical evidence such as an expert on the subject might give. The courts very generally agree in regarding the testimony of both as fit to go to the jury for their consideration. But when it comes to the question whether the blood is human blood or that of the brute animal, legal science will require a resort to chemical experts to determine this point. 8 It is important to determine by chemical analysis when blood spots are found on clothing, on which side of the clothing they were deposited. The ordinary witness could do but little here. To the expert, a chemical test reveals the position of the coloring matter of the blood, and he thus determines on which side of the garment the spot first touched. 9 In the detection of forged writing, and the nature and compounding of inks, the age of handwriting, etc., chemical experts have played an important part, especially in these later days of perfected appliances. The test would, of course, be something more than mere observation. As in that case no scientific knowledge or skill is involved.

  4. Micro-chemical examination of inks to determine age has been received in cases. And in all these tests much light appears to be thrown on the inquiry through the testimony and experiments of microscopists. The importance of such testimony is well known and is well illustrated in the case like that of Sheldon v. Warner. 10

  5. Evidence as Affected by the Opinions of Microscopists.—Upon the question of whether or not a certain exhibit is human hair, the opinion of an expert microscopist would be received, and a witness possessing no special skill as a microscopist has been allowed to testify in this case. In the famous Cronin case, but recently tried by a Chicago court, expert testimony on the subject of hair was received, and a number of microscopical experts gave testimony on both sides of the question. Some of these experts, notably Marshall D. Ewell, l2 of the Northwestern University, claimed that there were no known means of determining human hair from any other kind of hair, while others claimed that they could tell by microscopical test. But whatever be the truth of the contested point, it is certain that such expert evidence is duly respected by the court and the jury are left to determine where doctors disagree. Microscopical investigation plays an importent part in detecting handwriting, forgeries, and alterations, and also in determining the nature of different inks. A holograph will, in which alterations and interlineations appeared, has been admitted to probate upon the testimony of such an expert, that in his opinion the alterations were written at same time as the rest of the will. 13 An expert accustomed to the use of the microscope after the examination of a note by the use of his appliances, has been allowed to testify that one word had been erased in the body of the note and another substituted. 14 As to the age of writing, in a recent Nebraska case, 15 the opinion is expressed that the question of the age of a written paper is not one of science or skill so as to make admissible the opinion of an expert upon its mere in [**326**]spection. The court in giving the opinion seems to indicate, and we do not doubt such to be the law of evidence, that after a scientific analysis of the ink used, and such attendant experiments as would naturally be allowed in forming anything like a correct scientific conclusion, such testimony would then have been received. In the examination of blood spots the microscope is a great aid in determining whether it is human blood or not. Although if the blood has long been dried on the clothing, Taylor in his work on Med. Jurisprudence, says their [sic] is no certainty of either chemical analysis of microscopical examination aiding a correct conclusion. 16

  6. Evidence as Affected by the Opinions of Photographers and Photographic Copies.—Photography has been made an important aid to courts and public offlcials in these latter days. The delicate, but wonderfully powerful design of the camera, imitating as it does the most wonderful piece of the human organization, designed by the creator to enable the mind to properly comprehend and enjoy the the [sic] beauty of the universe, has given us the benefit of a beautiful art to aid science in its work. A distinguished expert in speaking of the photographical art in connection with showing the difference in inks used in a certain case says "the photograph is able to distinguish shades of color which are inappreciable to the naked eye; thus where there is the least particle of yellow present in a color, it will take notice of the fact by making the picture blacker just in proportion as the yellow predominates, so that a very light yellow will take a deep black. So any shade of green, or blue, or red where there is an imperceptible amount of yellow will print by the photographic process more or less black, while either a red, or blue, verging to purple, will show more or less faint as the case may be. Here is a method of investigation which may be very useful in such cases and which will give no uncertain answer." In the case of Town v. Parkersburg Branch R. R. Co., 17 the court held the testimony of photographers as not always reliable. In this case an offer to establish the forgery of certificates in controversy by a comparison with photographic copies of originals was made. The court said: "As a general rule, as the medin of evidence is multiplied the chance of error increases. Photography do not always produce fac-similes of the objects delineated, and however indebted we may be to that beautiful science for much that is useful as well as ornamental, it is at least a mimetic art which furnishes only secondary impressions of the original that vary according to the lights and shadows which prevail whilst being taken." The photographic art is not perfect, but it at least approaches nearer to perfection than any other known power of reproduction by copying process. It the court looked for perfect results in the applied test before it, the reasoning above is not to be wondered at. However, the reasoning in the case of Marcy v. Barnes, 18 is the very reverse of this. Photographers have been allowed to state an opinion as to whether photographs in evidence were well executed. 19 Photographic copies of the locus in quo are competent to go to the jury whenever it is important to show such fact. 20 Questions of identity of person have been established by photographs. 2l In these cases it is but fair to state that such photographic copies were received upon the theory that no better means of identification were at hand. Such evidence must of necessity be only secondary in its nature. The court said in the case of Udderzook v. Commonwealth, above cited: "The Daguerrean process was discovered in 1839 it was soon followed by photography. It has been customary, and a common mode of taking and preserving views as well as the likenesses of persons, and has obtained universal assent to the correctness of its delineations. We know that its principles are derived from science; that the image: on the plate made by the rays of light through the camera are dependent on the same general laws which produce the images of outward forms upon the retina through the lenses of the eye. The process has become one in gen[**327**]eral use, so common that we cannot refuse to take judicial cognizance of it as a proper means of producing correct likenesses." This seems better reasoning than that of the Maryland court. In the case of Leathers v. The Salvor Wrecking Company, 22 it was held that photographic copies of public documents on file in the public departments at Washington, which public policy requires should not be removed, are admissible in evidence when their genuineness is authenticated in the usual way. Photographic copies were not received with the depositions of witnesses living in another State who had stated their opinion of the genuineness of disputed handwriting, the opinion being based upon a photographic copy of the instrument in dispute attached to interrogatories. The conclusion reached by the court in this case 23 was that photographic copies of instruments sued on could only be used as secondary evidence, and rejected the testimony on the ground that no foundation had been laid for it. In the matter of Foster's will decided in 1876, 24 the court says: "If the court had permitted photogaphic [sic] copies of the will to be given to the jury with such precautions as to secure their identity and correctness, it might not perhaps have been error;" although the court in its conclusion passed against the admission of such copies. The same conclusion was followed in Maclean v. Scripps. 25 A photographed copy of a forged note that has since become illegible, is admissible to prove the words of the note upon proof that it is an exact copy of the words. 26 Percy Edwards Owosso, Mich.


  1. Plowden. 125.

  2. Commonwealth v. Hobbs, 140 Mass. 443; Commonwealth v. Kendrick, 147 Mass. 444. The admissibility of this testimony is very generally acknowledged by the other State courts.

  3. Joe v. State, 6 Fla. 591; People v. Milliard, 53 Mich. 74.

  4. The State v. Cook, 17 Kan. 394. See, also the suggestion of court in People v. Milliard, 63 Mich. 69.

  5. State v. Hinkle, Iowa, 380. In this case the opinions of two practicing physicians were admitted. One of them stated in answer to a question that he was not a professional chemist but understood some of the practical details of chemistry, that portion which belonged to his profession; that he had no practical experience in the analysis of poison until he analysed the contents of the stomach of the deceased; that he was previously acquainted with the means of detecting poisons, and had since then had some experience in that way. The other declared that he was not a practical chemist, but understood the chemical tests by which the presence of poisons could be detected; that he had never experimented with the view of detecting strychnine by chemical tests but that he had seen chemical tests by professors of chemistry and that there was one test much relied on, the trial of which he had witnessed. See for contra leaning, People v. Milliard, 53 Mich. 74. In a Michigan case it has been held (Peer v. Ryan, 54 Mich. 224), an expert's qualifications depend on experience and not upon his profession.

  6. Commonwealth v. Sturtivant, 117 Mass. 122, 124; State v. Knight, 43 Me. 1,183; Knoll v. State, 55 Wis. 249.

  7. Dillard v. State, 68 Miss. 368-86; People v. Greenfield, 30 N. Y. Sup. Ct. 462, 85 N.Y. 76; People v. Deacons, 109 N.Y. 374.

  8. The People v. Gonzalez, 35 N.Y. 49, 61.

  9. State v. Knight, supra. And the chemical expert may state what direction the blood stain took. See Commonwealth v. Sturtivant, 117 Mass. 122. But in a case decided in Mississippi some years ago where it was proposed to ask the experts to give their opinions as to the relative positions of the combatants at the time of the affray when blood was deposited on the shirt of the victim with a view of showing by the blood stain that the prisoner was probably prostrate on the ground and deceased on top of him when the stains were received, the court held against the submission of this testimony on the ground that it did not involve any matter for scientific research or special skill. Dillard v. State, 58 Miss. 368, 387.

  10. 46 Mich. 638.

  11. Commonwealth v. Dorsey, 103 Mass. 412.

  12. Also Dr. Lester Curtis and Prof. Harold Moyer.

  13. In re Goods of Hindmarch, 1 P. & M. 307.

  14. Dubois v. Baker, 3d N.Y. 366. In a case an expert has been allowed to state that one figure has been substituted for another; Nelson v. Johnson, 143 Ind. 329, and the cancelling of certain words; Beach v. O'Riley, 14 West Va. 55.

  15. Cheney v. Dunlap, 20 Neb. 265.

  16. See page 307, Taylor's Med. Juris.

  17. 39 Md. 693, 17 Am. Rep. 640.

  18. 16 Gray, 161.

  19. Barnes v. Ingalls, 39 Ala. 193.

  20. Randall v. Chase, 133 Mass. 210; Church v. City of Milwaukee, 31 Wis. 513; People v. Buddensick, 103 N.Y. 487, Bliss v. Johnson, 76 Cal. 597; Blair v. Pelham, 118 Mass. 421; Cozzens v. Higgens, 33 Howard Prac. Rep. 439. In Ruloff v. People, 46 N.Y. 45, same was held; Barker v. Perry, 67 Iowa, 146; Locker v. Sioux City, etc., R. R. Co., 46 Iowa, 109; Dyson v. N.Y., etc., R. R. Co., 57 Conn. 9.

  21. Udderzook v. Commonwealth, 76 Penn. St. 340; Marlon v. State, 20 Neb. 233; Ruloff v. People. 45 N. Y. 213; Brooke v. Brooke, 60 Md. 529.

  22. Wood, 682 (U.S.C.C.).

  23. Eborn v. Zimpelman, 47 Texas, 503.

  24. 34 Mich. 23.

  25. 52 Mich. 214, 219.

  26. Duffin v. People, 107 Ill. 113.