Comments on the Piltdown Remains
Robert F. Heizer and Sherburne F. Cook
American Anthropologist 1954
 In the light of our experience in investigating and evaluating fluorine and other constituents of archeological human and animal bone, we would draw the following conclusions from the data presented by Washburn (1953) in his Table 1. Neither of us has seen the 1953 report by Weiner, Oakley and Clark.
The jaw, molar and canine of Piltdown 1 and the molar tooth of Piltdown 2 we would regard as of very recent origini.e., modern in the temporal sense. The belief has been expressed in newspaper accounts, and apparently also by Weiner, Oakley and Clark, that these pieces were introduced into the gravel  by some unknown or unnamed person with the intent to deceive. This may be the case. If these four bones were on the other hand naturally interred (i.e., are indigenous to the gravels and not deliberately placed there as a hoax), the duration of interment could hardly have exceeded a span of time in excess of a few decades. This opinion derives from two facts: (1) the fluorine (F) content of the bones mentioned does not exceed the range found in fresh bone, and (2) the values for the nitrogen content (3.9, 4.3, 5.1 and 4.2 per cent) all lie at or above the average value for fresh human and animal bone, which is about 4.0 per cent (Cook and Heizer 1952, Table 5). Even a relatively short period of interment of the order of 100 to 300 years, as shown by burials in culturally late California sites, reduces the nitrogen content rapidly to not higher than 3.0 per cent. Inspection of our data for nitrogen content from 28 archeological sites shows a clear trend of decreasing nitrogen with age.
Referring again to Table 1 of Washburn's article, the Piltdown 1 skull and the (animal?) bone from the Upper Pleistocene, together with the frontal fragment of Piltdown 2, all give indication of moderate age. This is indicated by the value of 0.1 per cent of fluorine, which definitely exceeds the level in fresh bone, and values for nitrogen content ranging from 0.7 to 1.4 per cent . No fresh bone which could have been secured and interred in a field by an Englishman within this century could show this degree of nitrogen depletion. Specimens from archeological sites in California which are within this range of nitrogen content can usually be assigned cultural dates of more than 1,000 years. It is hardly necessary to state that a direct transfer from our local situation cannot be made to England, and this is not implied.
The last item cited by Washburn in his Table 1 and described as "occipital fragment of Piltdown 2" contains 0.03 per cent fluorine and 0.6 per cent nitrogen. This bone illustrates the undesirability of excessive dogmatism with regard to the dating of individual specimens. The low fluorine content implies a very recent origin since the fluorine content is within the range of very recent bone. On the other hand, the nitrogen value of 0.6 per cent indicates a relatively great antiquity, since it is the lowest value found in any of the Piltdown bone samples. On the basis solely of the two analyses presented, it is hypothetically possible to allocate this bone to any one of the following three categories: (1) a modern bone introduced as a hoax; (2) an archeological specimen removed from its original site elsewhere and introduced to the Piltdown locality, and (3) an indigenous bone in the Piltdown gravels. This conflict suggests the desirability of subjecting the sample to analysis for further constituents such as bound water, organic carbon, carbonate and calcium. Meanwhile we may express agreement with Washburn's opinion that the three samples which constitute Piltdown 2 are of entirely distinct and separate origin.
Analytic results of the Oakley-Hoskins 1950 determinations of the Piltdown materials which differ from those of 1953 are presumably to be taken as errors. They do not imply a lack of reliability of the fluorine method for deriving relative age of bones in the same bed. The large amount of investigation  by the fluorine method (see Oakley 1953); Heizer and Cook 1952) appears to support the validity of the technique.
Our experience with the chemistry of fresh and archeological bone leads us to suggest that if any question still remains as to the modern origin of the Piltdown mandible, this could be settled by analyzing for fat by the method first proposed by Gangi and discussed at length by Cook and Heizer (1952, 1-3). Furthermore, it would be desirable to have data on the other organic and inorganic compounds mentioned above. The interplay of all these methods is discussed with respect to the problems of dating by Cook and Heizer (1953a, 1953b).
The Piltdown episode emphasizes a conclusion which we drew in our reports, namely, that although one cannot set up a universal dating system based on chemical analysis of bone, nevertheless chemical analysis proves itself an exceedingly valuable tool in specific instances as, for example, in differentiating the skull and jaw of the Piltdown material. It is further interesting to note that the fluorine method has been available in its essentials (mainly through the efforts of Middleton and Carnot) for over a century, and that shortly after Carnot's major publication in 1893 the method was successfully applied to Mexico and the United States. Apparently the method did not appeal to the prehistorians and physical anthropologists of the period, and it fell into disuse. One unfortunate result has been that no person in England, where Middleton worked and published, until the time of Oakley, saw in the fluorine technique a ready means of solving the most difficult single problem of the Piltdown remains, which was the matter of the association of the mandible with the skull.
Cook, S. F. and R. F. Heizer
1952 The fossilization of bone: organic compounds and water. University of California
Archaeological Survey, Report No. 17. Berkeley.
1953a The present status of chemical methods for dating prehistoric bone. American Antiquity 18:354-58.
1953b Archaeological dating by chemical analysis of bone. Southwestern Journal of
Heizer, R. F. and S. F. Cook
1952 Fluorine and other chemical tests of some North American human and fossil bone.
American Journal of Physical Anthropology 10:289-304.
Oakley, K. P.
1953 Dating fossil human remains in Anthropology Today, pp. 43-56. Chicago, University of Chicago Press.
Washburn, S. L.
1953 The Piltdown hoax. American Anthropologist 55:759-62.