Henry Mills, 1813 - 1889

by Brian Stevenson
last updated February, 2023

After retiring from work, ca. 1870, Henry Mills enjoyed a second “career” as an amateur scientist. He became a world-renowned expert on freshwater sponges, and frequently published reports of their physiology and ecology. Mills was described as “one of the first to efficiently use the microscope in Buffalo (New York)”. He was a founder of that city’s microscopical society, and a ranking member of the American Society of Microscopists. Although he did not have an advanced degree or a scholarly appointment, Mills was often referred to as “Doctor” or “Professor” due to his wealth of knowledge and willingness to share with others.

Henry Mills’ microscope slides are well-made, with labels bearing his type-set name and address, and handwritten details of the specimen (Figure 1). His slides that are encountered nowadays probably came from his personal collection, or from exchanges with colleagues.

Figure 1. A Henry Mills microscope slide. He noted that the specimen was received 3 February, 1885. The specimen is tissues from the freshwater sponge Meyenia fluviatilis, and was obtained from Ditchling, Sussex, England. An 1885 publication on this sponge by H.J. Carter noted that Henry Mills had found this species in the Niagara River, not far from his home.


Figure 2. Details of Meyenia fluviatilis spicules, prepared in 1885 by Henry Mills (see Figure 1). Photographed with transmitted light, a 3.5x objective lens, and C-mounted digital SLR camera on a Leitz Ortholux II microscope.


Henry Mills was born on March 15, 1813, in Hertfordshire, England. The 1841 national census recorded that he was then working as a “British teacher” (English language teacher), and boarding in Ricksmansworth, Hertfordshire. On September 30, 1841, Henry married Mary Abbee in Ricksmansworth.

In June-July, 1848, Henry, Mary, their three young children, and 32 year-old Ann Mills (presumably Henry’s sister) emigrated to New York. Henry took work as a teacher in Darien, New York. Around the mid-1860s, the Mills family moved to Buffalo, New York. The 1865 and 1870 censuses describe his occupation as “melodeon tuner” (the melodeon is a keyboard instrument that is also known as the reed organ). Mills retired from employment during the early 1870s.

In 1872, Mills became the first Curator of Microscopy for the Buffalo Society of Natural Sciences. That appointment implies that Henry had already been a serious microscopist for some time. Mills was a founding member of the Buffalo Microscopical Club, in 1876. He served on the original Advisory Board, and later served as President. Mills joined the American Society of Microscopists in 1879, and regularly served administrative roles.

By 1879, Mills had become an expert in freshwater sponge biology. That year, he wrote a long paper on the subject for the Transactions of the American Microscopical Society. He wrote numerous additional papers on freshwater sponges, the last appearing at the time of his death.

A colleague of Mills’, Edward Potts, later wrote that Henry Mills “frequently expressed his vexation at the persistence with which would-be collectors of fresh water sponges, looked for jelly-masses to fill their ideals; and he sometimes told them they would never find a sponge until they stopped looking for jelly”.

An obituary stated that “Mr. Mills was not a species-maker, and often withheld a long time a description from publication, or in several instances sent his material and suggestions to others for publication”.

An example of Mills’ generosity and reluctance to name species is seen in Henry J. Carter’s 1885 paper “On a variety of the freshwater sponge Meyenia fluviatilis, auctt., from Florida”. Carter wrote, “Mr. Henry Mills, of Buffalo, in the discovery of freshwater sponges in his particular locality, and in the praiseworthy desire to advance the subject by sending specimens of them to European as well as American naturalists. Of the species in the Niagara River Mr. Mills has long since forwarded to me several handsome specimens for distribution among the museums in this country, and proposes to send more; hence I have already been able to enrich the collections of Spongillæ in the British and Liverpool Museums respectively to this extent. Not confining his researches to the Niagara River, Mr. Mills has also not forgotten the subject when abroad, although engaged in other matters probably of more importance, so that during his last two visits to Florida he has been almost equally successful there in his discovery of the freshwater sponges, and equally generous in sending about specimens of them on his return to Buffalo. One of them, which he has kindly sent to me, he has, at my suggestion, designated a variety of Meyenia fluviatilis, under the name of ‘gracilis’, and this, from his accompanying data, together with two slides and a bit of the sponge itself in spirit, I shall, at his request, presently describe for publication”. A Mills’ slide of Meyenia fluviatilis that was obtained from a colleague in England is shown in Figures 1 and 2, above.

These were the early days of the Germ Theory. In 1879, Henry Mills weighed in with support of a hypothesis that diphtheria might be caused by a fungus. The pseudomembrane produced during diphtheria resembles fungal colonies, so the mistake is not unreasonable. The model that Mills favored was that diphtheria is acquired by eating apples and other fruit that have fungus on them. He wrote, “The writer of this article as a microscopist has examined fruit this winter and has found the black spots on apples to consist of a fungus - one of the oidia. The spots vary in size from a pins head to a good sized pea. A small portion of the dark, downy tuft growing in the center of the spot when removed by the point of a pen-knife to a suitable slide and placed under the microscope, will show the fungus. Mycelium and threads and spores extending from these sometimes cover a large part of the apple as may be seen with even a low power of the instrument. Slides can easily be prepared so as to show the fungus either as opaque or transparent. The spores are inconceivably small, and thousands of them with the mycelium might lodge in the fauces without being felt, unless they should begin to germinate. The microscope reveals the fact that the decayed part of apples also is infested through and through with a similar fungus. … These remarks are not intended to discourage the plentiful use of good ripe and sound fruit, but from the facts stated, it must appear to be the duty of all who value their own health and the health of those depending on them to see that the fruit eaten is perfectly sound and clean out side and in”. Mills’ article was reprinted in a medical journal, which referred to him as “Dr. Henry Mills”.

Reports of the 1884 Annual Meeting of the American Society of Microscopists in The Microscope stated that “Dr. Henry Mills” was appointed to the Nominating Committee. Additionally, “Prof. Henry Mills, Buffalo, N.Y.” had a table at a working session in which he described “How to prepare sponges for mounting spicules”.

That 1884 working session would have been a very useful way for a microscope enthusiast to spend an afternoon. On 28 tables, experts demonstrated techniques such as, “Mounting fresh animal tissues”, “Mounting opaque objects in wooden cells”, “Cutting vegetable sections”, “Showing multiple images in compound eyes of insects”, “Silvering mirrors”, “Section cutting with freezing microtome”, “Preparing and mounting insects”, “Mounting mineral specimens”, and “Transferring microphotographs from charms to slides”.

At the 1886 Annual Meeting of the American Society of Microscopists, “Henry Mills, Buffalo, N.Y., exhibited microspectroscope showing, by way of illustrating its use, the absorption bands of various substances. He also exhibited a variety of fresh-water sponges, some of which were taken from Chautauqua lake a few hours before”.

Mills’ expertise in freshwater sponges allowed him to make the following observations, which were reported to The American Monthly Microscopical Journal in 1887: “I have a slide of diatoms from Ichabo guano of 1844, mounted by Topping. In looking it over, a few days ago, I noticed quite a large number of dermal spicula of the fresh-water sponge, Spongilla lacustris. There are also many skeleton spicula of several forms, but these may be marine, while the dermal spiculum, with its characteristic curves and spines, are unmistakably of the fresh-water species. There are also some half-dozen large and well-formed birotulate spicula, which are only known in fresh-water sponges. All this proving that the birds must have lived on food from fresh water. Having supposed that guano was the product of sea birds, which, as a matter of course, obtain their food from the ocean, I was surprised to find such evidence to the contrary. If you or any of your numerous readers can set me right in the matter, I shall be greatly obliged”. I have not discovered whether Mills’ query was answered.

In addition to microscopical studies, Henry Mills owned an astronomical telescope. The Smithsonian Institute listed Millls’ home as a “private observatory”. Mills stated that his “principal instrument is a telescope of 3-inch object-glass and 44-inch focus, which I use chiefly for the entertainment of my friends in viewing such celestial objects as come within range of such an instrument”. The Smithsonian reported that the telescope was manufactured by Bardou, of Paris, and was capable of 50x to 250x magnification. During 1880, Mills reported observations of sun-spots and comets.

Henry Mills died on February 7, 1889. The Microscope published the following obituary, naming him “Henry Mills, D.S.K.” – my best guess for those initials is that his colleagues honored Mills as “Doctor of Scientific Knowledge”:

This venerable and highly esteemed contributor to The Microscope, died after a brief illness February 7, 1889, in Chattanooga, Tenn., at the age of seventy-six. Mr. Mills was on his way to Florida, where he hoped to escape, as in previous years, the rigors of climate incident to his Northern home.

He is best known to the readers of this journal by his work on the Fresh-Water Sponges. Twelve or more years since, he retired from business and spent much of his leisure thereafter in collecting and studying these forms. This search had been carried on, not only about his home, Buffalo, N. Y., but in Florida, Pennsylvania, Ohio, Illinois, Wisconsin and Dakota. He was successful in greatly extending our knowledge of the distribution and habits of our species; he also gave the first notice and description of several new and unique species or varieties. Mr. Mills was not a species-maker, and often withheld a long time a description from publication, or in several instances sent his material and suggestions to others for publication. Those of us who, knowing him intimately, know that his modesty was equal to his worth, can understand this.

Success achieved in another direction, gave him the keenest pleasure and satisfaction, viz: that he had been able to assist others in getting a start in the study of nature with the microscope. In the progress of such he rejoiced as one may at the advancement of his own children. The writer of this note is one of many who has benefited by his advice, been inspired by his enthusiasm, led to respect him for his genuine manhood, and now revere his memory.

Mr. Mills was one of the first to efficiently use the microscope in Buffalo. He was the first Curator of Microscopy, Buffalo Society of Natural Sciences (1872); one of the founders of the Buffalo Microscopical Club (1876), serving almost constantly on its Board of Managers, one year as President, and contributing largely to its proceedings; he was a member, joining in 1879, of the American Society of Microscopists.

The subject of this sketch was an honored member of the Baptist Church, known and respected by all as a pure man and an honest man”.

A member of the American Postal Microscopical Club, Mills contributed to a box of slides that was in circulation at the time of his death. Mary Ann Booth, a professional slide-maker and editor of The American Monthly Microscopical Journal, wrote in early 1889 that “Box T recalls two members who have, since the issue of this box, passed on to fuller light and knowledge, Dr. L.M. Kenyon and Henry L. Mills, Esq … Slide No. 2 is a fresh-water sponge, by the late Henry Mills, Myenia fluviatilis, cleared in carbolic acid and mounted in Canada balsam. The preparation shows skeleton spicula, several statoblasts or winter eggs, with their birotulate spicules. No. 3 was contributed for the late Dr. Kenyon by Mr. Mills, a section of yellow water-lily, Nuphar lutea”.



The American Naturalist (1876) “Buffalo Microscopical Club, Buffalo, N.Y. Organized 1876. President, Prof. George Hadley, M.D.; Secretary, James W. Ward; Advisory Council, H.R. Hopkins, M.D., Henry Mills, and Prof. D.R. Kellicott”, Vol. 10, page 310

The American Naturalist (1876) “Society of Natural Sciences, Buffalo, N.Y.; Microscopical Section. Organized 1872. Curator, Henry Mills, 162 Fargo Ave.”, Vol. 10, page 311

Annual Record of Science and Industry (1878) “Buffalo, N.Y.: Private Observatory of Henry Mills, Esq. My principal instrument is a Telescope of 3-inch object-glass and 44-inch focus, which I use chiefly for the entertainment of my friends in viewing such celestial objects as come within range of such an instrument. Besides a report made to the Naval Observatory on the transit of Mercury on May 5 and 6, I have no special work to record”, Vol. 8, page 49

Annual Report of the Board of Regents of the Smithsonian Institution (1880) “Buffalo, Erie County, New York. Private Observatory. Longitude from Washington, 7m 218.65 W. Latitude, 420 54' 9.5 N. Authority for latitude and longitude: Report for 1862 of the Regents of University of State of New York. Director: Henry Mills. Instruments (a) Telescope, not equatorial; maker, Bardou; aperture of objective, 3 inches; for observations of the sun, aperture employed, 3 inches; magnifying power ordinarily employed, 50 to 250 diameters. Observations during the past year: Observations on sun-spots and comets and such other celestial phenomena as come within the range of the instrument.”, pages 628-629

Booth, Mary Ann (as “Queen Mab”) (1889) Report upon the Postal Club boxes, The American Monthly Microscopical Journal, Vol. 10, pages 131-132

Carter, Henry J. (1885) On a variety of the freshwater sponge Meyenia fluviatilis, auctt., from Florida, The Annals and Magazine of Natural History, Zoology, Botany and Geology, pages 179-181

England census and other records, accessed through ancestry.com

Find-a-Grave (accessed February, 2023) “Henry Mills, born March 16, 1813, died Feb. 7, 1889”, https://www.findagrave.com/memorial/146039096/henry-mills

Immigration record of Henry Mills and family (1848) accessed through ancestry.com

The Microscope (1884) Proceedings of the American Society of Microscopists, pages 208 and 234-235

The Microscope (1889) Obituary of Henry Mills, page 79

Mills, Henry (1879) A hot-house pest, and how to get rid of it, The American Journal of Microscopy and Popular Science, Vol. 4, pages 61-63

Mills, Henry (1879) Causes of diphtheria, Buffalo Medical and Surgical Journal, Vol. 18, pages 366-367

Mills, Henry (1879) Fresh-water sponge, Transactions of the American Microscopical Society, pages 209-216

Mills, Henry (1882) Microscopic organisms in the Buffalo water-supply and in Niagara River, Proceedings of the American Society of Microscopists, pages 165-175

Mills, Henry (1882) Motion of diatoms, The American Monthly Microscopical Journal, Vol. 3, pages 8-9

Mills, Henry (1882) Notes on the Spongillae of Buffalo, Bulletin of the Buffalo Society of Natural Sciences, Vol. 4, pages 57-60

Mills, Henry (1884) Serial arrangement of birotulate spicules in statoblasts of American sponges, The American Monthly Microscopical Journal, Vol. 5, pages 41-42

Mills, Henry (1885) Notes on fresh water sponges, Transactions of the American Microscopical Society, pages 132-139

Mills, Henry (1887) Letter to Editor, The American Monthly Microscopical Journal, Vol. 8, pages 17-18

Mills, Henry (1888) A new freshwater sponge, Heteromeyenia radiospiculata n. sp., The Microscope, Vol. 8, pages 52-53

Mills, Henry (1889) Fresh-water sponges, The Journal of Microscopy and Natural Science, Vol. 8, pages 82-85

Potts, Edward (1881) Some new Genera of fresh water sponges, Proceedings of The Academy of Natural Sciences of Philadelphia, pages 149-150

Potts, Edward (1890) Fresh water sponges, what they are not, The Microscope, pages 140-143

Proceedings of the American Society of Microscopists (1886) Vol. 8, page 190

Quarterly Epitome of Practical Medicine and Surgery (1880) Diphtheria – causes of, page 28

USA census and other records, accessed through ancestry.com