Microbiological, virological, bacteriological, immunological, medical, epidemiological, historical, anecdotal

Tag: occupational hazards

So you want to be an industrial glassblower

So, you’re interested in a job as a glassblower. That’s no surprise. For 50 years glassblowing has been a good way for a skilled industrial laborer to earn a comfortable living, and today as we enter the 1920s, demand for these workmen shows no signs of lessening. But what are the risks?

Since there are so many glassblowers around, it’s important for society to properly assess what diseases they are likely to suffer. Frederick L. Hoffman writes, in the 231st Bulletin of the United States Bureau of Labor Statistics (“Mortality from Respiratory Diseases in Dusty Trades”, 17th in the Industrial Accidents and Hygiene Series):

The hygiene of glass blowers with special reference to pulmonary tuberculosis is of exceptional interest as a labor problem in the glass industry. The number of blowers employed proportionate to the total number of wage earners is relatively large, and, from a wage point of view, the employment is of the first order of importance.

From this US government document we can see some statistics on the prevalence of tuberculosis in this population. It’s not so much that they are exposed to the bacteria to a high degree. But continual low-level lung damage by inhaling high-temperature air containing various dusts means that once the bacteria are inevitably inhaled, they have a place to roost. The lung equivalent of abrasions, you might say.


So they have higher mortality rates than men in general of the same age. With regard to tuberculosis in particular, here’s a table compiled by Prudential Insurance researchers.


Carboy blowing? Carboys are huge! It’s hard to contemplate the human lungs being the engines of inflation for one of these. Or thisHand Blown Monumental Demijohn.

Some other recent statistics, from the Chicago Tuberculosis Institute. This table is on page 153 of the July 1915 – June 1916 annual report of the Illinois Chief State Factory Inspector.


So as a glassblower you’re not as likely to fall prey to the dread tubercular bacillus as you would be as a marbleworker or upholsterer, but it’s a concern.

* * *

What about other lung conditions?

This turns out to be controversial. As a person with no medical training, I’d imagine that the risk factors for tuberculosis and emphysema are pretty similar. Inhaling poisons or microscopic things that damage the alveoli (alveoli are tiny air sacs which combine to make up a massive surface area for oxygen to enter the blood). However, the evidence regarding glassblowers suggests that the two diseases are uncorrelated.

In 1904 Prettin and Leibkind of the Stadtkrankenhaus Dresden-Friedrichstadt analyzed 230 glassblowers for an article entitled “Kann durch Glasblasen ein Lungenemphysem erzeugt werden?” JAMA (the Journal of the American Medical Association) deemed this an important finding, a perfect example of the sort of science-based result that supersedes old-fashioned beliefs that were based only on common sense.


* * *

We already know that the southeastern regions of New Jersey are great for making wines and wine-related medicinal concoctions. Meanwhile southwestern New Jersey was a hotbed of glass production, as seen in the history of the large town of Glassboro in Gloucester County. To the northeast are two townships called Waterford and Winslow, both of which are named for large glassworks that existed in the 1860s.

In 2006 Erik Schwartz of the Cherry Hill Courier-Post wrote about the long-gone legacy of glass in areas including Waterford and Winslow townships. And in 1869 Dr. John Snowden sent in some observations about the health of workers at the Waterford and Winslow glassworks, included in the Camden County report (p. 134-136) in the Transactions of the Medical Society of New Jersey. “Phthisis” means tuberculosis.


A very interesting communication on the subject of Phthisis has been received from Dr. John W. Snowden, who had practiced for more than twenty-three years at the seat of two of the largest manufactories of glass in this State — at the Waterford and Winslow glass manufactories, where several hundred hands are employed in the manufacture of glass. Dr. Snowden says that among the glass-blowers themselves Phthisis is not at all frequent; but that many of these operatives suffer from emphysema of the lungs. But that among the batch-makers (those who prepare and mix the materials of which the glass is composed), and also among the pot-makers, who make the pots in which the glass is melted in the furnaces, Phthisis is very common indeed, and that few can follow this branch of the business for many years without being liable to Phthisis.

Dr. Snowden says that many of those men, months after they have been compelled by the progress of the disease to leave off work, expectorate with tuberculous matter small masses of German clay, one of the materials of which the pots are made. This undoubtedly being drawn into the lungs by inspiration, in a state of fine powder, and being insoluble, is deposited in the tissue of the lung, where it serves as a point of irritation around which the tubercle is first deposited.

So now glass-blowers don’t get tuberculosis, but they do get emphysema? I guess it depends on the facility.

There is a lot of clay powder involved in glass-making, that’s for sure. Here are the ads at the top of three straight pages of the August 25, 1917 National Glass Budget.

pittsburg-clay-pot-co highlands-fire-clay-co-st-louis laclede-christy-clay-products

* * *

Really, a lot of risks that apply to other glassworkers do not apply to glassblowers. In terms of health hazards, one of the longest assessments was written in this series of articles for insurance men, highlighting how to avoid physical accidents and the subsequent payouts for broken bones, burns, deafness, that sort of thing. I don’t know exactly what it means by “Live Articles”. Maybe it means “This is the current standard of what we expect”.


Here’s a typical illustration.


The Travelers Insurance agent who wrote “Glass Manufacturing Hazards” for this series agrees that emphysema is not a major problem for glassblowers, despite what one might expect. The men who work with the raw glass ingredients, and the “bottle-breakers” who smash undesirable glass so it can be re-melted, are more at risk for this — as they are for skin irritation, painful abrasions, burns from molten glass, and foot lacerations.

Glass-blowers do sometimes break their teeth when the iron blow-pipe strikes some hard object. They slip on the smooth, worn wooden foot-benches that are often without railings. They drink too much water, causing cramps. They get blisters, which should, but usually aren’t, dealt with by puncturing the blister with a needle threaded with white sewing silk, to provide drainage before the blister bursts. And they get infectious diseases from the shared water cup used to cool down between blows, and more importantly, from the shared mouthpiece on the blow-pipe. This has been the subject of several studies. Studies of syphilis.

* * *

The first link between glass-blowers’ pipes and syphilis I can find is from 1862, when the British Medical Journal relayed a report from France. Apparently in “Giers and Vernasion” (which probably means Rive-de-Gier and Vernaison), transmitting diseases is virtually inevitable because the normal procedure is for three men to collaborate (taking turns in quick succession) on blowing a single piece of glass. Is this the normal method? Anyway, this leads to the men giving each other “the three syphilitic disease of the mouth”.


In a 1904 issue of the Indianapolis Medical and Surgical Monitor, Dr. Nelson D. Brayton of the Indiana Medical College collects a large number of reports under the title “Syphilis, a Non-Venereal Disease”. Along with dozens of other anecdotes of people acquiring the dreaded disease through innocent means, he mentions a 162-person outbreak of syphilis among glass-blowers, along with other professions where people risk disease by putting common instruments in their mouths (assayers, weavers, goldsmiths, train conductors, music teachers).

In his 1906 dissertation at the University of Würzburg, Joseph Kaesbohrer described 290 cases of syphilis in which the first observed chancre (hard sore) was seen in the tonsillar region. These frequently occurred from kissing and from nursing, as well as from medical instruments, shared eating utensils, and tobacco pipes. In a summary in the Medical Review of Reviews, the only occupation listed as a risk factor is glass-blowing. So be cautious. But should you acquire this or other so-called venereal disease from your blow-pipe, don’t fear rumors and innuendo, as Kaesbohrer found that “sexual perversion, which many have assumed to be a frequent cause, is, as a matter of fact, an infrequent cause of tonsillar chancre.”

* * *

Depending on what sort of glass works you find yourself in, the risk factors can be different. Most glass doesn’t have lead in it, but some does, and that’ll be bad if it ends up in your lungs, as seen in this 1920 case from Italy.

Unshielded eyes are at risk for “glass-blowers’ cataract”. One reason why we can’t see long-wavelength “infrared” light is that the lens of the eye absorbs this light instead of letting it through to the retina where we could perceive it. Long-term exposure to this light, which we can sense only as heat radiation, can lead to a forty-year-old having the cataracts of a man of eighty. According to the Illinois Medical Journal, the eminent Dr. de Schweinitz can look at the clouding of a furnace-worker’s eyes and tell if he is right- or left-handed.

Finally, a health consequence of glassblowing that may be the most obvious of all if you know someone who’s spent a couple decades in the job. From The Sanitarian, March 1892:

According to Le Progres Medicale, the Societe de Biologie, of which M. Brown-Sequard is president, received from M. Regnault, of Marseilles, at its session on November 7th, 1891, a communication on a disease which is met with in about one third of the workmen. This condition does not attain complete development until the men have been from ten to fifteen years in the business. They are taken into the glass factories, usually, about fifteen years of age; and at first the young workmen complain of great fatigue and a painful feeling in the cheeks which extends to the ears; later, the cheek becomes gradually weakened, is easily puffed out, and the deformity, of which the cases presented were in an advanced stage, progresses steadily. This deformity is caused principally by the weakness of the buccinator muscle, whereby the cheek becomes swollen and permanently enlarged.

The swelling is limited by the masseter muscle. There is also a special dilation of the duct of Steno, the calibre of which is increased and the orifice enlarged. This duct is filled with air, which may be forced out by pressure on the external surface, when a distinct gassy sound is heard.

In short, after years of glass-blowing, your face may be altered. The buccinator muscle is weakened, the cheeks expand into jowls, and the inner mucous lining “is thrown up into vertical and circular folds, giving it an appearance which has been likened to that of a tobacco-pouch.”

Neither M. Regnault of Marseilles nor Dr. Liaras of Bordeaux, summarized in “The Mouths of Glass-Blowers” in the June 1898 Medical Bulletin, see these altered facial features as a serious problem. But in severe cases, the primary salivary duct (the parotid duct, a.k.a. duct of Stensen, a.k.a. duct of Steno) is forced open by the intense pressure in the mouth, and it becomes dilated, forcing air into the salivary gland. I can’t imagine what that feels like. Maybe not painful, but certainly weird. It sounds like a fun party trick to be able to puff up your salivary glands on command… but when it happens unbidden at work, it’s a problem. The final citation on this subject comes from JAMA of November 23, 1912.


So, the word “Tumor”. This is not “tumor” as in cancer, it’s the form that simply means “swelling”. As in the four elements of inflammation, rubor/calor/dolor/tumor, defined by Celsus in the first century A.D. Air goes into the parotid gland, and then you have “tumor” in the parotid gland. As described here by the surgeon Narath, you may have to quit your job if the “chronically stretched duct and gland” get too bad. But you’ll always have the party trick.

* * *

And one more thing. Yet another German article paraphrased by a English-language journal, in this case the March 1899 Canada Lancet.


“Luxation of the eye”? “Proptosis”? Does that mean… yes, just search for some images. So with your newly enhanced lung power as a glass-blower, just make sure that when you sneeze, really let that sneeze escape. Don’t keep it bottled up, if you value your eyeballs’ position behind their eyelids. And good luck!

Pit pony work dust factor

It has long been known that coal dust is one of the least harmful of all the dusts inhaled industrially. Since the practice of laying down stone dust in coal mines was adopted, however, a certain degree of uneasiness has been felt as to the possible effect of the stone dust on the collier’s lung.

With a somewhat dubious reassurance of the safety of coal dust (“least harmful dust inhaled industrially” is kind of like “least fattening cheesecake eaten voraciously”), F. Haynes of the University of Oxford begins an investigation(*) of the real menace to coal miners’ lungs: stone dust. To combat explosions, ground-up stone is applied inside mine shafts, diluting the highly combustible coal dust.

  1. How much dust ends up in a miner’s lungs?
  2. Does it get worse and worse over, say, a 20-year career?
  3. How much lung damage does this produce?

To answer these questions, Haynes got mines to send him lung samples from various workers who either died on the job or were euthanized when they became unable to work. Not human miners — pit ponies, who were employed in large numbers before the advent of mechanized rail cars.

Coal miners and pit pony, 1913. Source:, which inserts this photo into random entries for people who happened to be coal miners.

Coal miners and pit pony, 1913. Source:, which inserts this photo into random entries for people who happened to be coal miners.

To cut a long story short, the answers are:

  1. Lots of dust.
  2. No, it gets worse for about 2 years and then stays about the same.
  3. Not much damage.
  4. This does not apply to extremely dusty dusts, like those from fireclay or Bute clod(**).

And how did he measure dust, to answer 1 and 2?

Dust was quantified as “dust value”, graded from 0 (horse that did not live in a mine shaft) to 10.

To look for a relationship between quantity of dust and time spent in the mine, Haynes created the “work-dust factor”. This is simply a ratio of “dust value” to the number of years spent mining. If you have a dust value of 6 and have been working for 11 years, your work-dust factor is (6 / 11) or 0.545. If the dust keeps accumulating year after year, everyone’s work-dust factor should be similar. But as you can see from this table, as ponies keep working, their work-dust factor decreases.


Which means… as ponies keep working, their dust levels stay about the same. This becomes clear if we multiply the number of years by the “work-dust factor”. Which just gives us the original dust value that we started with. Which is about the same for all groups.

For combining two simple numbers into a confusing metric that was never used again by anyone, F. Haynes receives a special posthumous commendation in the fields of toxicology and biostatistics.

Samples of Haynes's pony pathology reports

Samples of Haynes’s pony pathology reports

* * *

Those wacky women and the etiology of their silly poisoning symptoms

In 1864, epidemiology as we know it didn’t exist. For example, the word “epidemiology” barely existed. Merriam-Webster claims the word dates to circa 1860, and Random House says 1870-75. John Snow’s great work was only a decade earlier.

Whatever the terminology, the study of disease outbreaks was a long way from being a statistical discipline. The best evidence that something led to disease, whether infectious disease or some sort of poisoning, came from collections of anecdotes and case studies, like the two presented by William S. Barker, M.D. in the January/February 1864 issue of the St. Louis Medical and Surgical Journal. This piece was reprinted in the Pacific Medical and Surgical Journal, volume VII (1864): 140-142, a journal which contains a lot of excerpts or “selections” from other publications. I don’t know if the original St. Louis journal has been digitized. The Pacific editors spotlighted these selections to publicize the return of the St. Louis journal, which had apparently been on a three-year hiatus.


The first case is G. W. E——–, a blue-collar worker who responds with “no” to all the doctor’s queries about whether he’s been ingesting arsenical food prepared by incompetent strangers, or patent medicines prepared by charlatans. The doctor thinks his symptoms look like poisoning rather than infection. It turns out that in his job casting molds at a foundry, he uses a lot of oil of vitriol (sulfuric acid) to get sand out of the molds. Dr. Barker remembers that arsenic poisoning occurred in other people exposed to oil of vitriol, for example people who use it in the manufacture of hydrochloric acid. At this time H2SO4 was made from heating of iron pyrite which contained arsenic impurities. After being told to stop inhaling so much sulfuric acid, the patient recovers. Simple and straightforward.

Final paragraph:

He was quite ill for ten days, but recovered perfectly. I think the case worthy of notice, as the cause of the disease was at first obscure, yet so unequivocal when understood.

* * *

In presenting the second case, Dr. Barker decides to lighten the mood, and gets all snarky, in a kind of way. But he probably would not enjoy, because his japes and quips are at the expense of “vain women” and women with intellectual pretensions. First, the poet Cowper is quoted for the purpose of establishing the fact that women use makeup. Then it is revealed that apparently some women seek to change their appearance not entirely to look winsome and nubile, but also in risible attempts to appear intelligent. This is accomplished by enhancing the height of one’s forehead, by physical or chemical hair removal.

Unkown lady, possibly Isabella de' Medici, by Bronzino (1503-1570)

Unkown lady, possibly Isabella de’ Medici, by Bronzino (1503-1570)

I know nothing about this, but my guess is that this was a simple case of following fashion trends, as there were certainly several instances in history of an exaggerated high forehead being the goal of the fashionable women of high society. Presumably it was associated with intelligence. But it’s a bit of a stretch to say, as Barker does, that it’s an attempt to resemble men, men being synonymous with brainpower.

Such delicate carnal glories have no charm for them. They are women of self-presumed intellectual power; as nature has unquestionably given to man a preponderance of intellect, they would look like men “as far as in them lies.” But there are only a few females to whom nature has given a broad and lofty brow. “The dome of thought, the palace of the soul,” is a somewhat diminutive tenement. Broad shoulders and a stentorian voice will not avail the strong-minded female, if the hair grows low on the forehead.

Yes, of course. Women’s heads are smaller than men’s, and to compensate, they want their hairlines to recede.

So Dr. Barker had a patient who tried to elevate her forehead by hair removal. Much like Mr. G. W. E——–, he anonymizes her name in an objective way, to “Miss Ophelia McDunder”. And in her case, it was the dreaded patent-medicine man who convinced her to poison herself, with a three-part hair removal technique consisting of Spanish fly to raise blisters, a powder of arsenic, and wax to fix everything in place under a bandage. This would prevent hair from growing back post-shaving. After four days of application, she was very sick and called the doctor. After removing the plaster, “her convalescence was tedious”, which is a medical term meaning slow.

In the course of describing this, Dr. Barker goes on various flights of fancy using mock-elevated language and poetic allusions, the Simpsons references of their day.

  • “the personal attractions of one of Eve’s fair daughters”
  • “she has undergone a scientific metamorphosis”
  • “perverse nature had renewed the growth”
  • “she utters maledictions ‘not loud, but deep'”

Final paragraph:

The above case furnishes a warning to quacks who use depilatories, and silly women who would deform themselves with second-story foreheads.

* * *

Volume VII of the Pacific Medical & Surgical Journal can be found in Google Books form here (starting with a handy index). Or search the web for “Miss Ophelia McDunder”. Or search for “vanity’s unwearied fingers”, since this paper is apparently the only case of that particular work of the poet Cowper being digitized or excerpted.

The all-male world of 19th-century medicine did not lead all its practitioners to adopt a condescending attitude. For a more respectful treatment of women being poisoned by cosmetics, see Lewis A. Sayre, M.D. (1869), Three cases of lead palsy from the use of a cosmetic called “Laird’s Bloom of Youth”: Transactions of the American Medical Association XX: 561-572. And that one is available here.