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Morton, Samuel George

Morton, Samuel George 1799–1851

Samuel George Morton, anatomist, physician, and “ethnologist,” has been called the father of physical anthropology in America. Morton was born in Philadelphia, and his Irish immigrant father died when the boy was only six months old. His mother enrolled him in Friends’ boarding schools for his education. The visits of many doctors during his mother’s illness in 1817 brought Morton into contact with the medical profession. After her death, he entered the service of Philadelphia physician Dr. Joseph Parrish and earned his medical degree from the University of Pennsylvania in 1820 (Hrdlička 1943). At the same time, he was elected into the Philadelphia-based Academy of Natural Sciences.

After attaining his degree, Morton traveled to Ireland to visit his uncle, James Morton, with whose financial support he undertook further medical training at the University of Edinburgh (Stevens 1856). At Edinburgh, Morton encountered the phrenologist George Combe and became acquainted with the most current trends in craniological research. This included phrenology, in the midst of a wave of support across Europe, as well as the researches into racial differences by Johann Blumenbach.

When he returned to Philadelphia to establish his medical practice in 1824, Morton also pursued his interest in natural history. This interest was quite varied: Some of his earliest scientific work concerned the description of fossils from Cretaceous and other geological contexts, including his description of invertebrate fossils collected by Lewis and Clark (Morton 1834). He was elected to the American Philosophical Society in 1828, and became professor of anatomy at Pennsylvania College in 1839 (American Philosophical Society 2002). During his early career he also advanced within the ranks of the Academy of Natural Sciences, attaining the office of secretary in 1831. Ultimately, he acceded to the presidency of the academy in 1849; by this time he had become one of the most celebrated scientists in the United States.

Morton attained renown for his study of the cranio-logical variation between human races. What made the work distinctive was Morton’s large collection of skulls, which at the time of his death was the largest such collection anywhere in the world. Morton acquired skulls by correspondence with naturalists, scientific authorities, explorers, and many others. In some instances, he exchanged skulls to build his collection, some were gifts, and others came at considerable expense. After Morton’s death in 1851, his collection was entrusted to the Academy of Natural Sciences and was augmented by further skulls solicited by Morton and others. The collection was later housed at the University of Pennsylvania Museum, where it continued to be a valuable resource for anthropological and medical research.

Morton’s first major work of anthropological import was the book Crania Americana (1839), in which he investigated the craniological characters of present and ancient Americans in relation to the races of the Old World. This book is notable for Morton’s conclusions that all the indigenous peoples of the Americas shared a common origin, that their features at once join them together and render them distinct from the races of the Old World and that these craniological differences were present in ancient specimens from the Mound Builders. Because of the antiquity of these cranial characters, Morton inferred that racial differences must have been inherent from creation, not induced by the environment or climate later in history. Crania Americana is notable for Morton’s relatively neutral approach to measurement and comparison, as he did not interpret the features in phrenological terms, although he did include an essay on this subject by George Combe, who held that Native Americans but not blacks were naturally “savage” and impervious to training.

The interpretation of racial antiquity was the subject of his second major work, Crania Aegyptaica (1844). Morton had acquired a substantial sample of ancient Egyptian remains through the efforts of the American consul to Alexandria, George R. Gliddon. Gliddon himself argued for the antiquity of races based on pictorial representations on ancient Egyptian monuments. On the basis of the crania, Morton concluded that racial differences were in fact as pronounced 4,000 years or more ago as in the present day. This result conflicted with the belief in unitary origins of humanity, as described in Genesis, and Morton approached a polygenic interpretation of human races. Polygenism was developed further by Gliddon and Josiah Knott, who argued for the specific diversity of Europeans and Africans.

Like most of his contemporaries, Morton took for granted an implicit ranking of human races. Accepting Blumenbach’s five-race categorization, Morton focused particularly on cranial capacity as the important factor differentiating them in terms of mental capacity. In his measurements, Caucasians (Europeans) sat at the highest rank, proceeding through Mongolians (Asians), Malay, Americans, and Ethiopians (Africans) at the lowest cranial capacity. He assumed a one-to-one relationship between cranial size and intelligence level. According to an 1849 study by Morton, his skull size measurements yielded these results: English skulls capacity, 96 cubic inches; Germans and Americans, 90 cubic inches; blacks, 83 cubic inches; the Chinese, 82 cubic inches; and Native Americans, 79 cubic inches (Gossett 1963, p. 74)

These results and his researches into the antiquity of racial differences gained political importance, as Morton— at the urging of Gliddon—advised Secretary of State John C. Calhoun on African racial qualities in support of the continuation of slavery (Stanton 1960) as a positive good.

In the late twentieth-century, Morton’s empirical work came under scrutiny. After reanalysis of Morton’s data tables, paleontologist Stephen Jay Gould suggested that Morton’s summary statistics reflected “unconscious finagling,” reinforcing interracial differences (Gould 1978, 1981). Gould noted a number of potential biases, in particular the inclusion of a higher proportion of small and female crania—as well as Australians—in Morton’s “African” sample, the exclusion of small “Hindu” crania from Morton’s “Caucasian” sample, and apparent discrepancies between measurements of the same crania taken using shot versus seed. However, a later consideration of these points by Michael (1988) found that Gould had mischaracterized Morton’s tables and had disregarded errors that weighed against Morton’s racial ranking. Michael interpreted Morton’s work as having been “conducted with integrity” (1988, p. 353), although the work did contain errors and sample biases attributable to the haphazard collection strategy.

Morton’s death in 1851 followed several years of illness from pleurisy, during which his work slowed. He was survived by his wife of twenty-four years, Rebecca Grellet Pearsall, and all eight of their children.

SEE ALSO Cranial Index; Genesis and Polygenesis; Racial Hierarchy.


American Philosophical Society. 2002. “Background Notes.” In Samuel George Morton papers. Philadelphia: American Philosophical Society. Available from

Gossett, Thomas F. 1963. Race: The History of an Idea in America. Dallas, TX: Southern Methodist University Press.

Gould, Stephan Jay. 1978. “Morton’s Ranking of Races by Cranial Capacity: Unconscious Manipulation of Data May Be a Scientific Norm.” Science 200: 503–509.

_____. 1981. The Mismeasure of Man. New York: Norton.

Hrdlička, Ales. 1943. “Contribution to the History of Physical Anthropology in the United States of America, with Special Reference to Philadelphia.” Proceedings of the American Philosophical Society 87 (1): 61–64.

Michael, J. S. 1988. “A New Look at Morton’s Craniological Research.” Current Anthropology 29: 349–354.

Morton, Samuel G. 1834. Synopsis of the Organic Remains of the Cretaceous Group of the United States. Philadelphia: Key and Biddle

_____. 1839. Crania Americana; or, a Comparative View of the Skulls of Various Aboriginal Nations of North and South America. Philadelphia: J. Dobson.

_____. 1844. Crania Aegyptiaca; or, Observations on Egyptian Ethnography Derived from Anatomy, History, and the Monuments. Philadelphia: J. Pennington.

Stanton, William. 1960. The Leopard’s Spots: Scientific Attitudes Toward Race in America 1815–59. Chicago: University of Chicago Press.

Stevens, A. 1856. “Samuel George Morton and Ethnology.” The National Magazine 9: 336–343.

John Hawks

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