HISTORY 135F

Infectious and Epidemic Disease in History

Department of History
University of California, Irvine
 Instructor:    Dr. Barbara J. Becker

Week 8.  Contact?

excerpts from
On the Nuisances Removal and Diseases Prevention Act
testimony delivered by Dr. John Snow on March 5, 1855

120.  [Chairman, Sir Benjamin Hall]--To what points would you desire to draw the attention of the Committee as regards the sanitary question?
[Dr. Snow]--I have paid a great deal of attention to epidemic diseases, more particularly to cholera, and in fact to the public health in general; and I have arrived at the conclusion with regard to what are called offensive trades, that many of them really do not assist in the propagation of epidemic diseases, and that in fact they are not injurious to the public health.  I consider that if they were injurious to the public health they would be extremely so to the workmen engaged in those trades, and as far as I have been able to learn, that is not the case; and from the law of the diffusion of gases, it follows, that if they are not injurious to those actually upon the spot, where the trades are carried on, it is impossible they should be to persons further removed from the spot.
121.  [Chairman]--Are the Committee to understand, taking the case of bone-boilers, that no matter how offensive to the sense of smell the effluvia that comes from bone-boiling establishments may be, yet you consider that it is not prejudicial in any way to the health of the inhabitants of the district?
[Dr. Snow]--That is my opinion.
122.  [Mr Greene]--Does that extend to all animal substances?
[Dr. Snow]--No.  I believe that epidemic diseases are propagated by special animal poisons coming from diseased persons, and causing the same diseases to others, and that they are extremely injurious; but that substances belonging to animals, that is to say, ordinary decomposing animal matter, will not produce disease in the human subject.
123.  [Mr Greene]--Do you apply that, also, to decaying vegetable matter; do you consider that that will not be productive of disease?
[Dr. Snow]--I do not believe that decaying vegetable matter would be productive of disease; at least, it is a matter open for discussion whether certain decomposing vegetable substances, in marshy districts, may not produce agues; but in London, in any trade I am acquainted with, I do not believe that any decomposing vegetable or animal matters produce disease.
124.  [Chairman]--Take the case of a bone-boiling establishment, or a knacker's yard; assuming that there is a large number of horses in a state of decomposition, from which of course there would be very offensive effluvia, as far as the sense of smell is concerned, do you apprehend that that would not be prejudicial to the health of the inhabitants round?
[Dr. Snow]--I believe not.
125.  [Mr Adderley]--Have you never known the blood poisoned by inhaling putrid matter?
[Dr. Snow]--No; but by dissection wounds the blood may be poisoned.
126.  [Mr Adderley]--Never by inhaling putrid matter?
[Dr. Snow]--No; gases produced by decomposition, when very concentrated, will produce sudden death; but where the person is not killed, if the person recovers, he has no fever or illness.
127.  [Mr Egerton]--You mean to say, that the fact of breathing air which is tainted by decomposing matter, either animal or vegetable, will not be highly prejudicial to health?
[Dr. Snow]--I am not aware that it is, unless it be in such quantities as to produce actually fatal effects at the moment; but to produce those effects it requires that it should be highly concentrated.
128.  [Mr Egerton]--Do you not know that the effect of breathing such tainted air often is to produce violent sickness at the time?
[Dr. Snow]--Yes, when the gases are in a very large quantity, as in a cesspool.
129.  [Mr Egerton]--Do you mean to tell the Committee that when the effect is to produce violent sickness there is no injury produced to the constitution or health of the individual?
[Dr. Snow]--No fever or special disease.
130.  [Mr Greene]--Are you not aware that persons going into vaults where there are a number of dead bodies have suffered very severely, and that sometimes death has been produced by this cause?
[Dr. Snow]--Yes, when those gases are extremely concentrated, they will actually poison a person and cause death, but not cause disease; those poisons do not reproduce themselves in the constitution.
131.  [Mr Greene]--Are you not aware that, in cases of this kind, illness has sometimes been produced from which persons have suffered for a considerable length of time before death ensued?
[Dr. Snow]--I am not satisfied upon that point.  If illness has followed I think it has been a coincident.
132.  [Mr Greene]--Are you not aware that, in cases of this kind, illness has sometimes been produced from which persons have suffered very severely, and that sometimes death has been produced by this cause?
[Dr. Snow]--Yes, when those gases are extremely concentrated, they will actually poison a person and cause death, but not cause disease; those poisons do not reproduce themselves in the constitution.
133.  [Mr Egerton]--You say that the effluvia arising from living subjects are dangerous?
[Dr. Snow]--Or even from certain persons who have died from disease....
138.  [Chairman]--I understand you to say that such effluvia, when highly concentrated, may produce vomiting, but that they are not injurious to health.  How do you reconcile those two propositions?
[Dr. Snow]--If the vomiting were repeatedly produced, it would certainly be injurious to health.  If a person was constantly exposed to decomposing matter, so concentrated as to disturb the digestive organs, it must be admitted that that would be injurious to health; but I am not aware that, in following any useful trade or manufacture, the effects ever experienced.
139.  [Chairman]--You consider that occasional sickness would be of no consequence, but that only frequent occurrence of the attacks would be injurious?
[Dr. Snow]--I am not aware that any occasional sickness is produced in any useful trade or manufacture.
140.  [Mr Egerton]--Do you not know that the effect of a very strong offensive smell often is to produce vomiting?
[Dr. Snow]--The gases must be very concentrated to do that, except it be by a kind of sympathy.  Persons are often much influenced by the imagination....
144.  [Mr Wilkinson]--Have you turned your attention to the effects of the late outbreak of cholera in London?"
[Dr. Snow]--Yes, I made special enquiries throughout Lambeth and Southwark and Newington.
145.  [Mr Wilkinson]--Have you satisfied yourself by those inquiries of any particular results of that outbreak of cholera, so as to state your opinion of what has been the mode of propagation of the disease?
[Dr. Snow]--I have satisfied myself completely, that the chief mode of propagation of cholera in the South district of London, throughout the late outbreak, was by the water of the Southwark and Vauxhall Water Company containing the sewage of London; and containing consequently whatever might come from the cholera patients in the crowded habitations of the poor; and I am satisfied that it spread directly from individual to individual, sometimes in the same family, but by similar means; that is, by their swallowing accidentally what came from a previous sick patient.
146.  [Mr Wilkinson]--Do you believe that there is evidence to show that cholera has been propagated almost entirely by the poison being taken in at the mouth?
[Dr. Snow]--Yes.
147.  [Mr Wilkinson]--Absolutely swallowed?
[Dr. Snow]--Yes, it is my belief in every case.

 
Go to:
  • On the Mode of Communication of Cholera (1855), by John Snow, M.D. (1813-1858)
  • "Observations on the Filth of the Thames," a letter to the Times of London (July 7, 1855) by Professor Michael Faraday (1791-1867)
  • "Monster Soup commonly called Thames Water, being a correct representation of that precious stuff doled out to us..." (ca. 1828) by William Heath (1795-1840)
  • News articles from the Chicago Tribune:
    • "They Deal in Death...," August 20, 1893;
    • "Caused by Microbes...," November 23, 1893
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