The Piltdown Fraud: Available Evidence Reviewed1
J. S. Weiner and K. P. Oakley2
American Journal of Physical AnthropologyMarch 1954
 The Chemical Evidence (K.P.O.)
A number of anthropologists from Waterston, Miller and Boule upwards have stated categorically that the Piltdown mandible is that of an ape; but they all assumed that it was of Pliocene or Lower Pleistocene age. In September, 1948, following the successful application of the "fluorine test" to the Galley Hill skeleton and Swanscombe skull, it was decided to drill small samples from the Piltdown mandible, canine and cranial fragments, and to compare their fluorine content with that of the fossils of various ages recorded from the site. The analyses were carried out by Dr. C. R. Hoskins in the Department of the Government Chemist, London, and the results indicated beyond doubt that the cranial bones, mandible and canine were all considerably younger than Lower Pleistocene. They were estimated to contain on an average 0.2% F, compared with 2.0% F in Lower Pleistocene specimens. No appreciable difference between the fluorine content of the cranium and of the mandible or teeth was noted, but the experimental error on samples of the very small size tested was large enough to obscure such a difference if it were less than 0.1%. Assuming that all these specimens were fossils it was concluded that the cranial bones, the mandible and  the canine tooth were all of the same relatively late age, probably Upper Pleistocene.
From an anatomical point of view this made it even more difficult to accept the mandible and canine as belonging to the same individual as the brain-case. The existence of an ape in Britain in Upper Pleistocene times was equally difficult to conceive. The Piltdown puzzle seemed insoluble until Weiner suggested in July, 1953, that the mandible and canine might be those of a modern ape treated so as to simulate fossils. The fluorine content of the mandible as recorded in 1949 (0.2%) had not appeared to allow that solution, but as it was based on analysis of only a few milligrams of material, re-determination of the fluorine content was required to test this hypothesis. New samples of the critical specimens were submitted to the Department of the Government Chemist, where they were analyzed by Mr. C. F. M. Fryd, using an improved technique making it possible to estimate small amounts of fluorine more accurately. The results showed that, whereas the Piltdown cranium might be Upper Pleistocene, as claimed in 1949, the mandible and canine tooth were modern.
Minimum in local Upper Pleistocene bones and teeth . . . 0.1
Piltdown cranial bones . . . . . . . 0.1
Piltdown mandible . . . . . . . <0.03
Piltdown molar . . . . . . . . <0.04
Piltdown canine . . . . . . . . <0.03
Recent molar . . . . . . . . <0.06
When the mandible was being drilled deeply with a dental burr to procure an adequate supply for the re-determination of fluorine, there was an odor of burning, and the ejection consisted of minute shavings. When the cranial bones were drilled in the same way there was no odor, and the sample consisted of powder.
Chemical studies of bones from early occupation sites in North America by Cook and Heizer have shown that, in bones buried under the same conditions, the nitrogen content is a rough guide to antiquity. Mrs. A. Foster (who, with Dr. J. D. H. Wiseman, in the Department of Minerals of the British  Museum, recently perfected a method of determining the nitrogen content of microgram samples) undertook the estimate of nitrogen in samples of the critical Piltdown specimens and selected controls. The results confirmed the evidence obtained from fluorine analysis.
Fresh bones and teeth . . . . . . . c.4.0
Piltdown mandible . . . . . . . . 3.9
Piltdown molar . . . . . . . . 4.3
Piltdown canine . . . . . . . . 5.1
Piltdown cranial bones . . . . . . . c.1.4
Local Upper Pleistocene bones and teeth (provisional estimate) . . < 1.5
The dentine of the canine proved to be pure white below a blackish film of some flexible paint-like substance, the precise nature of which is still being investigated.
Woodward ('48) stated that the pieces of skull which were first discovered had been dipped by Dawson in a solution of potassium dichromate, with the mistaken idea that this would harden them. The cranial fragments found while Woodward was digging with Dawson at Piltdown have not been chromium stained. The mandible on the other hand, although found in Woodward's presence, is chromate stained, indicating that it was treated prior to its reported extraction from the gravel, i.e., it had been "planted." (The chromate staining of the specimens was tested by Drs. M. H. Hey and A. A. Moss in the Department of Minerals at the British Museum, and by Mr. E. T. Hall in the Clarendon Laboratory, Oxford.)
It is possible that the specimens were steeped first in gelatine and then in a dichromate solution, for this is a rational means of hardening soft specimens. However, if the gelatine were the source of the greater part of the nitrogen detected in the specimens, the cranial bones which are porous should contain more nitrogen than the compact dentine of the teeth, whereas the reverse is true.
Analyses have also been made of the frontal and occipital fragments which were recorded as being found at a second site together with an isolated molar tooth which Hrdlicka  ('30) regarded as almost certainly from the Piltdown mandible of the first site. The frontal fragment of "Piltdown II" could, anatomically, form part of the cranium of Piltdown I, with which it agrees in its fluorine and nitrogen content. The occipital fragment, on the other hand, does represent another individual, but it contains no more fluorine than some recent bones (0.03%). Its nitrogen content is low (0.6%), but in a bone which may have been exposed on the surface for some time this is no proof of antiquity (whereas high nitrogen content in a bone from an oxidized deposit is a clear indication of relative modernity). It has been suggested that this piece was artificially stained to match the color of the more mineralized frontal fragment. 3
EVIDENCE OF THE WEAR OF THE TEETH (J.S.W.)
The composition of the mandible and of the canine leaves no doubt that they are modern. The evidence of the staining and also of artificial abrasion shows that they were not only modern but fraudulent.
Before discussing this evidence further, it may be of interest to recount how anatomical considerations led to the strong supposition that the Piltdown remains were in part a fake.
That the mandible is overwhelmingly ape-like is a fact which was, of course, stressed by Smith Woodward from the beginning, and has been demonstrated in detail by many others, of whom in particular should be mentioned Waterston ('13) and Miller ('15). Marston ('52) has insisted on the similarity of the canine to that of an upper canine of a modern orang. When reconsidering the Piltdown problem in July this year, the point which emerged particularly was that there appeared to be only a single feature of the jaw and dentition which could not be said to be definitely ape-like, namely, the wear of the molars and canine. It seemed surprising, on anatomical as well as evolutionary grounds, that this should be the only undoubted feature to link the cranium and the mandible. This feature alone prevented the jaw from being ascribed to a modern ape, for the 1949 fluorine analysis (Oakley and Hoskins, '50) had not only removed it from the Lower Pleistocene dating, but had left its antiquity rather indeterminate, and even allowed one to suppose that one was not necessarily dealing with a fossil. Moreover, in the same paper, Oakley recorded that the canine under the thin "ferruginous" layer was astonishingly white and fresh. The question became simplyhow could such peculiar wear have been produced in a mandible, possibly quite modern, and which doubtless possessed an ape's glenoid articulation? The possibility that the teeth had been artificially worn down obtained strong initial support from the fact that the nature of the wear of the canine has always been so baffling.
The evidence of artificial abrasion is as follow:
Molar teeth of the mandible.
1. The occlusal surfaces (particularly of M2) are planed down over almost their whole extent to a flatness which is much more even than that normally produced by natural wear.
2. The borders of the flat occlusal surfacesparticularly the lateral bordersare sharp-cut and show no evidence of the bevelling which is usually produced by natural wear.
3. The center of the talonid basin in M2 is unworn, and is bounded by a sharp-cut and unbevelled border of the planed surface of the crown. This appearance would be produced by artificial abrasion, but would not be expected in natural wear.
4. The surface of the areas of dentine exposed on the antero-medial cusps of the two molars is quite flat and flush with the surrounding enamel, instead of forming a depression as would be expected in natural wear.
5. In both molars much more dentine has been exposed on the antero-internal than the antero-external cusps. But, in the course of natural attrition, the lateral cusps of lower molar teeth are normally worn down more rapidly (and thus  usually show a great exposure of dentine) than the medial cusps.
6. The degree of wear in the two molars, Ml and M2, is almost identical. But in early stages of natural attrition, M1 is commonly (though not always) more severely worn than M2.
7. The planes of the flat occlusal surfaces of the two molars are not congruous, i.e., they do not fit together to form a uniform contour.
8. Inspection of the isolated molar tooth ("Piltdown II") with a binocular microscope shows that the occlusal surface of the enamel has been finely scratched as though by an abrasive.
1. The mode of wear of this tooth is unlike that found normally in ape or human canines, for the abraded surface has exposed the dentine over the entire lingual surface from medial to distal border, and at one point actually reaches the apex of the pulp cavity.
2. The condition of the apex of the root, and the wide and open pulp cavity seen in an x-ray photograph, indicate fairly certainly that the canine was still incompletely erupted or had only just recently completed its eruption. But this would be incompatible with the severe attrition of the crown if the latter were naturally produced.
3. X-ray examination shows no evidence of the deposition of secondary dentine (with a constriction of the pulp cavity) which might be expected if the severe abrasion of the lingual surface of the crown were the result of natural attrition.
4. The abraded surface of the crown shows fine vertically disposed scratches (as seen under a binocular microscope) which suggests the application of an abrasive.
In the discussion at the Geological Society (Nov. 25, 1953), Marston ignored the chemical evidence as well as the other facts presented by Oakley. He did not produce any data in support of his claim that the mandible is that of a fossil ape, other than a reference to slight and quite equivocal features in the morphology of the jaw and the canine. Indeed, he has taken considerable pains in his recent papers to emphasize the close anatomical similarities which the jaw and teeth bear to modern simian, and particularly orang, specimens. On the other hand, he has merely offered a quite hypothetical explanation for the production of the dental wear in this postulated fossil ape. The presence of sand grains in the canine was the only point which Marston brought forward as evidence of fossilization of this tooth, quite ignoring its high nitrogen content, its low fluorine content, the fact that the so-called ferruginous layer is flexible, that the heavy wear is in complete contradiction to the size of the pulp cavity, and the absence of secondary dentine. The sand grains are, in fact, not consolidated, and are quite loose; they could thus have been inserted deliberately.
In summary, then, we have in the Piltdown mandible and teeth specimens which are quite recent. The features of the wear are not to be found in those of modern apes, and have been produced, as they could only have been produced, by deliberate interference.
Lastly, it should be recorded that the identity of the hoaxer still remains unknown.
1 Based on the preliminary report in the Bulletin of the British Museum (Natural History), Geological Series, Vol. 2, No. 3, "The Solution of the Piltdown Problem," by J. S. Weiner, K. P. Oakley and W. E. Le Gros Clark, 1953, and on a Discussion at the Geological Society of London, November 25, 1953.
2 We are deeply grateful to Prof. W. E. Le Gros Clark for allowing us to quote from his anatomical observations on the Piltdown dentition.
3 Further chemical evidence bearing on this question will be presented in the second paper on the Piltdown Problem, to be published in a forthcoming part of the Bulletin of the British Museum (Natural History).
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