# Gary N. Calkins
Gary Nathan Calkins (January 18, 1869 – January 4, 1943) was an American protozoologist at Columbia University who spent his career on the reproduction, life history, and aging of single-celled organisms, and who was elected to the National Academy of Sciences in 1919 in the discipline of Cellular and Developmental Biology.[1](https://nasonline.org/member-directory/deceased-members/20001060.html) The National Academy describes him as a leading figure in the study of single-cell life forms during the first half of the twentieth century.[1](https://nasonline.org/member-directory/deceased-members/20001060.html) His central scientific problem was whether ciliates such as *Paramecium* can divide indefinitely without sex, or whether they age and die unless they conjugate.[2](http://encyclopedia-loadbalancer-1-1782916326.us-west-2.elb.amazonaws.com/science/dictionaries-thesauruses-pictures-and-press-releases/calkins-gary-nathan)
| Fact | Detail |
|---|---|
| Born | January 18, 1869, Valparaiso, Indiana[3](https://id.loc.gov/authorities/names/n87818742.html) |
| Died | January 4, 1943, Scarsdale, New York[3](https://id.loc.gov/authorities/names/n87818742.html) |
| Training | SB, MIT, 1890; PhD, Columbia, 1897, under Edmund B. Wilson[1](https://nasonline.org/member-directory/deceased-members/20001060.html) • [4](https://centuryarchives.org/member-directory/?PersonID=463&Search=0f40f4ebe3dc3c816bfbb766c2e6b84f) |
| Signature work | *Paramecium* life-history series, 1901–03 (A series died in its 590+ generation); "Restoration of Vitality Through Conjugation," PNAS, 1919[5](https://doi.org/10.1002/jez.1400010305) • [6](https://doi.org/10.1073/pnas.5.4.95) |
| Professorship | Professor of protozoology at Columbia from 1907, the first to be so designated[7](https://news.hrvh.org/veridian/?a=d&d=scarsdaleinquire19430108.2.44) |
| NAS election | 1919[1](https://nasonline.org/member-directory/deceased-members/20001060.html) |
| Best-known books | *The Protozoa* (1901), *The Biology of the Protozoa* (1926)[1](https://nasonline.org/member-directory/deceased-members/20001060.html) • [2](http://encyclopedia-loadbalancer-1-1782916326.us-west-2.elb.amazonaws.com/science/dictionaries-thesauruses-pictures-and-press-releases/calkins-gary-nathan) |
## Early life and training
Calkins was born in Valparaiso, Indiana, on January 18, 1869, the son of John and Emma Smith Calkins, and entered the [Massachusetts Institute of Technology](https://www.edgepedia.org/massachusetts-institute-of-technology) at the age of sixteen.[7](https://news.hrvh.org/veridian/?a=d&d=scarsdaleinquire19430108.2.44) Having earned his bachelor's degree in 1890, he then worked as microscopist for the Massachusetts State Board of Health under Professor William T. Sedgwick.[4](https://centuryarchives.org/member-directory/?PersonID=463&Search=0f40f4ebe3dc3c816bfbb766c2e6b84f)
In 1893 he came to Columbia University as a graduate student in the recently established Department of Zoology to pursue advanced studies under Edmund B. Wilson.[4](https://centuryarchives.org/member-directory/?PersonID=463&Search=0f40f4ebe3dc3c816bfbb766c2e6b84f) He received his PhD in 1897.[3](https://id.loc.gov/authorities/names/n87818742.html)
## Career at Columbia
His Columbia career began before his degree was finished: he was made a tutor in biology in 1894 and appointed instructor of zoology in 1899.[7](https://news.hrvh.org/veridian/?a=d&d=scarsdaleinquire19430108.2.44) In 1907 he was named professor of protozoology, the first to be so designated.[7](https://news.hrvh.org/veridian/?a=d&d=scarsdaleinquire19430108.2.44) He was one of nineteen Columbia faculty members retiring in 1939, becoming professor emeritus in residence effective June 30, 1939.[8](https://news.hrvh.org/veridian/?a=d&d=scarsdaleinquire19390526.2.39)
The NAS directory places his MIT teaching from 1890 to 1906 and his move to Columbia in 1906; the contemporary obituary and the Library of Congress record instead have him at Columbia as a graduate student from 1893, tutoring from 1894.[1](https://nasonline.org/member-directory/deceased-members/20001060.html) • [7](https://news.hrvh.org/veridian/?a=d&d=scarsdaleinquire19430108.2.44) • [3](https://id.loc.gov/authorities/names/n87818742.html) The obituary chronology, written with the dates in hand and corroborated by the Library of Congress, is the more detailed of the two.
## Representative work
**The life-history experiments.** Calkins kept lines of *Paramecium caudatum* dividing asexually for over 20 continuous months. The B series died out in May 1902 in its 450+ generation; the A series died on December 19, 1902, in its 590+ generation; a third series, started in June 1902, died out in June 1903 in its 300+ generation.[5](https://doi.org/10.1002/jez.1400010305) The result was a measured lifespan for a single-celled lineage, in generations, and it anchored his claim that a ciliate line left without conjugation runs down and ends.[2](http://encyclopedia-loadbalancer-1-1782916326.us-west-2.elb.amazonaws.com/science/dictionaries-thesauruses-pictures-and-press-releases/calkins-gary-nathan)
**Which exconjugant is renewed.** Since 1876 it had been generally assumed that conjugation renews vitality in both exconjugants, an assumption Calkins pointed out had never been submitted to experimental proof. In twenty pairs of *Paramecium* cultivated after separation from conjugation, one individual of each pair invariably outlived the other, which he read as an incipient fertilization like that in metazoa rather than a mutual rejuvenation.[9](https://doi.org/10.3181/00379727-2-26)
**Against protozoan immortality.** [August Weismann](https://www.edgepedia.org/august-weismann)'s doctrine held that Protozoa, lacking differentiated somatic cells, have no natural death and are potentially immortal. In a 1911 article Calkins argued that this view must be abandoned: in the vast majority of Protozoa there is a clearly defined equivalent of somatic cells and an equivalent of natural death.[10](https://en.wikisource.org/wiki/Popular_Science_Monthly/Volume_79/December_1911/Protozoan_Germ_Plasm) He developed the argument in "Cycles and Rhythms and the Problem of 'Immortality' in *Paramecium*" in *The American Naturalist*, published February 1, 1915.[11](https://doi.org/10.1086/279459)
**Conjugation restores vitality.** In a paper that Edmund B. Wilson communicated on January 15, 1919, Calkins described how one ex-conjugant of *Paramecium*, isolated on November 24, 1917, established a line sustained through about 250 generations by division, which died out on September 18 after its vitality had become progressively reduced.[6](https://doi.org/10.1073/pnas.5.4.95) The same paper reported experiments on the ciliate *Uroleptus mobilis* and concluded that conjugation actually restores waning vitality to full metabolic vigor.[6](https://doi.org/10.1073/pnas.5.4.95)
## Textbooks and monographs
Calkins published *The Protozoa* with The Macmillan Company in July 1901; the [Dictionary of Scientific Biography](https://www.edgepedia.org/dictionary-of-scientific-biography) calls it one of the two earliest modern works on the subject and the first in English, while the National Academy calls it the earliest English-language book on the subject.[2](http://encyclopedia-loadbalancer-1-1782916326.us-west-2.elb.amazonaws.com/science/dictionaries-thesauruses-pictures-and-press-releases/calkins-gary-nathan) • [1](https://nasonline.org/member-directory/deceased-members/20001060.html) It was reprinted in July 1910, a decade after first publication, and carried a chapter on senile degeneration in Protozoa and renewal of youth through the union of two individuals, and the bearing of these phenomena on sexual reproduction in general.[12](https://archive.org/details/cu31924001026727) Over the years he produced several extremely influential textbooks of protozoology, and his views reached maturity in the widely cited *The Biology of the Protozoa* (1926), a 634-page volume with a general bibliography and a special bibliography at the end of each chapter.[2](http://encyclopedia-loadbalancer-1-1782916326.us-west-2.elb.amazonaws.com/science/dictionaries-thesauruses-pictures-and-press-releases/calkins-gary-nathan) • [13](https://archive.org/details/biologyofprotozo00calk) The Century Association record describes his volumes on the biology of the Protozoa as standards in zoological science.[4](https://centuryarchives.org/member-directory/?PersonID=463&Search=0f40f4ebe3dc3c816bfbb766c2e6b84f)
## Later assessments
The conjugation question made Calkins a party to a decades-long controversy over whether ciliates can continue indefinitely to maintain themselves by division without conjugation. His colleagues considered his views a one-sided approach to vital processes and to reproduction and regeneration.[2](http://encyclopedia-loadbalancer-1-1782916326.us-west-2.elb.amazonaws.com/science/dictionaries-thesauruses-pictures-and-press-releases/calkins-gary-nathan)
The problem he studied has outlasted the controversy. A September 2024 preprint on the origin of cellular senescence in ciliates argues that renewal of the macronucleus is mechanistically tied to conjugation: without conjugation a cell cannot renew its macronucleus, the macronucleus degenerates, and the lineage eventually fails. The preprint frames this as an evolvability adaptation, but a costly one, and asks how renewal of the macronucleus came to be tied to conjugation at all.[14](https://www.biorxiv.org/content/10.1101/2024.09.17.613400v1) That framing is close to the position Calkins defended: a ciliate lineage left without sex runs down and ends.[2](http://encyclopedia-loadbalancer-1-1782916326.us-west-2.elb.amazonaws.com/science/dictionaries-thesauruses-pictures-and-press-releases/calkins-gary-nathan)
## References
1. Gary Calkins, NAS Member Directory (Deceased Members), https://nasonline.org/member-directory/deceased-members/20001060.html
2. "Calkins, Gary Nathan," Encyclopedia.com (Dictionary of Scientific Biography), http://encyclopedia-loadbalancer-1-1782916326.us-west-2.elb.amazonaws.com/science/dictionaries-thesauruses-pictures-and-press-releases/calkins-gary-nathan
3. Library of Congress Name Authority Record: Calkins, Gary Nathan, 1869-1943, https://id.loc.gov/authorities/names/n87818742.html
4. Gary N. Calkins, Century Archives Member Directory, https://centuryarchives.org/member-directory/?PersonID=463&Search=0f40f4ebe3dc3c816bfbb766c2e6b84f
5. Gary N. Calkins, "Studies on the life history of protozoa. IV. Death of the A series. Conclusions," Journal of Experimental Zoology (1904), https://doi.org/10.1002/jez.1400010305
6. Gary N. Calkins, "Restoration of Vitality Through Conjugation," PNAS 5 (1919), https://doi.org/10.1073/pnas.5.4.95
7. "Professor Calkins Dies At Walworth Ave. Home," Scarsdale Inquirer, January 8, 1943, https://news.hrvh.org/veridian/?a=d&d=scarsdaleinquire19430108.2.44
8. "Professor Emeritus," Scarsdale Inquirer, May 26, 1939, https://news.hrvh.org/veridian/?a=d&d=scarsdaleinquire19390526.2.39
9. Gary N. Calkins, "Rejuvenescence in protozoa" (1905), https://doi.org/10.3181/00379727-2-26
10. Gary N. Calkins, "Protozoan Germ Plasm," Popular Science Monthly 79 (December 1911), https://en.wikisource.org/wiki/Popular_Science_Monthly/Volume_79/December_1911/Protozoan_Germ_Plasm
11. Gary N. Calkins, "Cycles and Rhythms and the Problem of 'Immortality' in Paramecium," The American Naturalist (1915), https://doi.org/10.1086/279459
12. Gary N. Calkins, *The Protozoa*, Macmillan, 1901, https://archive.org/details/cu31924001026727
13. Gary N. Calkins, *The Biology of the Protozoa*, 1926, https://archive.org/details/biologyofprotozo00calk
14. "Origin of Cellular Senescence in Ciliates," bioRxiv, September 2024, https://www.biorxiv.org/content/10.1101/2024.09.17.613400v1
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