The late 19th century was roughly the beginning of what we may call the modern era of medical science. But they might as well have been in the dark ages compared to today. Far too many people romanticize the past. For most folks back then life was short and brutish.
On top of all the deadly diseases we don’t even give a thought to in the modern world, we were busy trying to kill each other off with insane levels of industrial pollution and contaminated food, water and even medicines. I read a book once that examined food processing during the height of the industrial revolution along with the levels of air and water pollution and I honestly don’t know how we survived as a species. Some of what was discussed made me physically nauseous.
As just one example... meat packers used to soak their product in formaldehyde and market it as “preserved meat.” According to the book, the embalming fluid gave the meat a sweet taste and made it very popular. It wasn’t until the early 1900’s that the practice was exposed. Fortunately, most people in those days didn’t eat nearly as much meat as we do. Still the practice likely contributed to infant and child mortality rates and made a lot of adults sick w/o them knowing why.
From family stories and my own reading about Victorian/Edwardian American and the British Empire, adulterated foodstuffs was common in big cities and moderately large ones too. Those who lived on farms and fed themselves via what they raised weren't as exposed to adulterated foods; however, neither did they often eat all that well due to weather conditions and social strata.
In London, Manchester, and other such places, one was more apt to contract and possibly die from Cholera than adulterated food ( though not lack of food ) and/or air pollution.
As shown in WW I...the average Brit recruit was much, much smaller than those from the aristocracy and those who worked on Aristos huge "country piles".
And while the available medical norms of that time seem somewhat crude to the modern mind, today, it was extremely advanced in terms of where it been just a short time earlier. For but one example...the first appendectomy was performed in London in the early 1700s; however, it wasn't until the the very late 1800s that it was taken seriously and done to save lives in London and i8n America too.
It was a time of only marginal science-based innovation. And because very little was known about the risks from chemicals, often the reaction to them was strong, but confused.
For example, adding copper compounds to canned peas and beans to make them greener.
(shortened link in case above link is broken)
Public hygiene taught in schools didn’t make a serious appearance until WWII. So while doctors knew of such, the public were often superstition driven.
Major health advances came from the use of carbolic acid (phenol) antiseptic, the widespread building of rural outhouses, efforts at mosquito abatement, and the Pure Food and Drug Act, after the publication of Upton Sinclair’s The Jungle, which exposed the gross nature of the meat industry.