I've written about this before, so I'm quoting the transcript from a podcast I did about the subject (http://bedside-rounds.org/episode-35-sherlock/ to listen). Transcript below. The TL;DR: the "white coat" is a lab coat, taken from laboratory science, and transferred to initially the operating room in the 1870s; from there, it transitioned to the standard for HOSPITAL medicine by the early 20th century, and by the 50s and 60s to the remainder of doctors (in the OR, it evolved in the white surgeons down, then into the blue and green surgeons scrubs). Why? Likely because of an association with science (new scientific medicine), and the association with cleanliness (this is the period of antisepsis, anesthesia, and the birth of modern surgery). The major symbol for physicians prior to this was the matula (http://longstreet.typepad.com/.a/6a00d83542d51e69e20120a6711034970c-pi), and for surgeons the lancet. If you were to go back all that way to 500 CE or so, the symbol was the Rod of Asclepius (https://cdn5.vectorstock.com/i/1000x1000/11/34/rod-of-asclepius-vector-18611134.jpg).
Referenced artwork:
https://en.wikipedia.org/wiki/The_Anatomy_Lesson_of_Dr._Nicolaes_Tulp
https://en.wikipedia.org/wiki/The_Gross_Clinic
https://en.wikipedia.org/wiki/The_Agnew_Clinic
Hope that helps.
Feelings about white coats run deep. I waste enough time on reddit to know that ever six months or so, some student or doctor will complain about the “watering down” of the symbolism of the white coat -- usually because a non-MD is wearing it. So like Tony asks -- where did the tradition of the white coat come from? It’s a far more recent tradition than you’d expect. Prior to the end of the nineteenth century, doctors would wear formal attire, similar to other professionals in their social class. This effectively meant a black suit, with either a tie or cravat. Take, for example, Thomas Eakins’ portrait of Dr. Samuel Gross, from 1875. I’ve posted it to my Twitter. Dr. Gross, his assistants, and his nurse are all dressed in black formal dress. Even the piece of artwork I use for a logo -- the Anatomy Lesson of Dr. Nicolaes Tulp -- which is FAR older, from 1632, shows the physicians gathered around the executed criminal in formal blacks.
So where did the white coat come from? Let’s just say the people who call it a lab coat are 100% correct. Two trends intersected in the late 19th century to bring us the white coat. The first is the German research university, a union of laboratory research with medical education. This model was wholeheartedly adopted in the United States, the primary example being Johns Hopkins, but also around the world. The second is Joseph Lister and the invention and widespread adoption of antisepsis in surgery, with a new focus on cleanliness in the operating room. Doctors had long used aprons in surgery to keep themselves clean. But now the focus was on not spreading microorganisms to patients on the surgical table. At some point, the lab coat jumped from the lab into the operating room. There were practical reasons, of course -- it was light colored (tan or beige, initially, then white) so contamination could easily be seen. But the symbolism also proved powerful. With the recent invention of anesthesia, and now antisepsis, surgery had dramatically improved, and the color white was associated with the new cleanliness of scientific surgery. It proliferated throughout the operating theaters -- the sheets, the gowns (white coats were abandoned by surgeons rather quickly), and even the nursing uniforms. Take a look at the Agnew Clinic, also painted by Thomas Eakins, in 1889. This is the same artist only 14 years later, but it’s a dramatic difference. The room is brightly lit, with Dr. Agnew clad in a white gown, as are his two assistants. His nurse, Mary Clymer, is also wearing a white uniform. And quite interestingly, the anesthesiologist, Dr. Ellwood Kirby, is wearing what we would today identify as a short white coat.
So, by the late 19th century, white garb had become standard gear in operating rooms. But take a look at that painting again -- all of the observers, who are presumably students and other doctors, are wearing formal black attire. There’s a photograph I want you to look at now, from May 1, 1908, in the Bigelow Amphitheater at Mass Gen. In this picture, the surgeons and anesthesiologists are all dressed in white gowns, including caps. They also have what appears to be leather gloves on as well, another innovation. There are some surgeons in the audience who are also dressed in the same white surgical gowns. But most of the audience is still wearing formal suits -- except one gentleman in the far left corner, dressed in a remarkably modern-looking white coat. So when did this spread happen? Dr. Blumhagen, who wrote pretty much THE article on the history of the white coat, looked at house officer photos at the Mass General Hospital in Boston -- and it was about in this period, between 1905 to 1915, when residents started to shed the formal black for the white coat. The reason appeared to be the symbolism, rather than any sort of practicality -- apparently the coats were cleaned by hand by the hospital, and stains were hard to get out. Nursing uniforms were also made white in this period, associated with further professionalizing the field away from its religious roots. It’s no coincidence that this period saw the white coat start to metastasize from the operating room. The Flexner Report was published in 1910, and soon after scientific medicine became the formal curriculum in new medical schools modeled after the German research universities. The association with science, cleanliness, and purity of the color white was too powerful to pass up. A guide to running a hospital from 1912 actually dictated that all people connected with the healing process were to wear white -- and all non-clinical personnel were forbidden from wearing it.
So by the 1930s, you pretty much have the white coat as it is currently used today -- but mostly on physicians working in a hospital. Doctors in private practice largely continued to wear professional street clothes, and surgeons switched to light blue or light green colored scrubs as the glare from new electric lights on white cloth made operating too difficult. Over the ensuing decades, it continued to spread beyond the hospital, and became so associated with the entire field of medicine, that in 1993 the first “white coat ceremony” was held, in which first year medical students are ceremonially cloaked in their short white coats.
