During the summer of 1851 Dr. W. M. Ryer was employed to vaccinate those Indians in the San Joaquin Valley who could be persuaded to undergo the operation. Each month Dr. Ryer submitted a voucher specifying the number of Indians vaccinated during the preceding thirty days and also mentioning the tribes and areas covered. These vouchers are included with other documents in Senate Executive Document No. 61, 32nd Congress, first session, 1852 (pp. 20 to 23). Some question might be raised concerning the accuracy of the figures, but there is no indication in the correspondence of the period of irregularity or dishonesty. Dr. Ryer claimed that he had vaccinated, from the Stanislaus to the south shore of Lake Tulare, 6,154 persons. A somewhat smaller area was covered by four of the eighteen treaties concluded by commissioners McKee, Barbour, and Wozencraft[1] with the California tribes in 1851. These four treaties may be designated A, B, C, and N, following the order in which they are presented in the Senate Report. Under the agreements, one of the commodities which were to be furnished to the Indians by the government was blankets. The tribes included under treaties A, B, and C were to receive a total of 3,000. In treaty N (as also in several other treaties not concerned with this area) it was stated that the Indians were to receive one blanket apiece for every person over fifteen years of age, and presumably this ratio was employed universally in the issue of blankets. Under the conditions existing at that time it may safely be assumed that the persons over fifteen years of age constituted at least 80 per cent of the total population. Therefore the three treaties first mentioned (A, B, and C) must have covered 3,750 individuals. Regarding the group embraced by treaty N it is explicitly stated that "they may number ... some 2,000 to 3,000." If we take the mean, or 2,500, then the total for the area is 6,250. The area included under the four treaties extended actually only from the Chowchilla River to the south shore of Lake Tulare and the Kern River, whereas the territory covered by Ryer during his vaccination tour began with the Stanislaus. Within the treaty limits he vaccinated 4,449 persons. The discrepancy between his total and that of the treaties poses no difficulty since it is apparent that, as would be expected with any primitive group, fewer individuals consented to be vaccinated than made known their desire to receive gifts of blankets. Hence the figure derived from potential blanket distribution is probably closer to the actuality than the vaccination figure. If, accordingly, we correct Ryer's report of 1,705 persons vaccinated _north_ of the Chowchilla River to conform to the ratio found south of that stream, we get 2,398. If we add this to 6,250 the total is 8,648 for the entire strip from the Stanislaus to the southern end of the San Joaquin Valley.