SCIENTIFIC INQUIRY: INVENTION AND TEST 2.1 A case history as an example As a sim
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SCIENTIFIC INQUIRY: INVENTION AND TEST 2.1 A case history as an example As a simple illustration of some important aspects of scientific inquiry let us consider Semmelweis' work on childbed fever. Ignaz Semmelweis, a physician of Hungarian birth, did this work during the years from 1844 to 1848 at the Vienna General Hospital. As a member of the medical staff of the First Maternity Division in the hospital, Semmelweis was distressed to find that a large proportion of the women who were delivered of their babies in that division contracted a serious and often fatal illness known as puerperal fever or childbed fever. In 1844, as many as 260 out of 3,157 mothers in the First Division, or 8.2 per cent, died of the disease; for 1845, the death rate was 6.8 per cent, and for 1846, it was 11.4 per cent. These figures were all the more alarming because in the adjacent Second Maternity Division of the same hospital, which accommodated almost as many women as the First, the death toll from childbed fever was much lower: 2.3, 2.0, and 2.7 per cent for the same years. In a book that he wrote later on the causation and the prevention of childbed fever, Semmelweis describes his efforts to resolve the dreadful puzzle.1 He began by considering various explanations that were current at the time; some of these he rejected out of hand as incompatible with well-established facts; others he subjected to specific tests. One widely accepted view attributed the ravages of puerperal fever to "epidemic influences", which were vaguely described as "atmospheric-cosmic-telluric changes" spreading over whole districts and causing childbed fever in women in confinement. But how, Semmelweis reasons, could such influences have plagued the First Division for years and yet spared the Second? And how could this view be reconciled with the fact that while the fever was raging in the hospital, hardly a case occurred in the city of Vienna or in its surroundings: a genuine epidemic, such as cholera, would not be so selective. Finally, Semmelweis notes that some of the women admitted to the First Division, living far from the hospital, had been overcome by labor on their way and had given birth in the street: yet despite these adverse conditions, the death rate from childbed fever among these cases of "street birth" was lower than the average for the First Division. On another view, overcrowding was a cause of mortality in the First Division. But Semmelweis points out that in fact the crowding was heavier in the Second Division, partly as a result of the desperate efforts of patients to avoid assignment to the notorious First Division. He also rejects two similar conjectures that were current, by noting that there were no differences between the two Divisions in regard to diet or general care of the patients. In 1846, a commission that had been appointed to investigate the matter attributed the prevalence of illness in the First Division to injuries resulting from rough examination by the medical students, all of whom received their obstetrical training in the First
2 Division. Semmelweis notes in refutation of this view that (a) the injuries resulting naturally from the process of birth are much more extensive than those that might be caused by rough examination; (b) the midwives who received their training in the Second Division examined their patients in much the same manner but without the same ill effects; (c) when, in response to the commission's report, the number of medical students was halved and their examinations of the women were reduced to a minimum, the mortality, after a brief decline, rose to higher levels than ever before. Various psychological explanations were attempted. One of them noted that the First Division was so arranged that a priest bearing the last sacrament to a dying woman had to pass through five wards before reaching the sickroom beyond: the appearance of the priest, preceded by an attendant ringing a bell, was held to have a terrifying and debilitating effect upon the patients in the wards and thus to make them more likely victims of childbed fever. In the Second Division, this adverse factor was absent, since the priest had direct access to the sickroom. Semmelweis decided to test this conjecture. He persuaded the priest to come by a roundabout route and without ringing of the bell, in order to reach the sick chamber silently and unobserved. But the mortality in the First Division did not decrease. A new idea was suggested to Semmelweis by the observation that in the First Division the women were delivered lying on their backs; in the Second Division, on their sides. Though he thought it unlikely, he decided "like a drowning man clutching at a straw", to test whether this difference in procedure was significant. He introduced the use of the lateral position in the First Division, but again, the mortality remained unaffected. At last, early in 1847, an accident gave Semmelweis the decisive clue for his solution of the problem. A colleague of his, Kolletschka, received a puncture wound in the finger, from the scalpel of a student with whom he was performing an autopsy, and died after an agonizing illness during which he displayed the same symptoms that Semmelweis had observed in the victims of childbed fever. Although the role of microorganisms in such infections had not yet been recognized at the time, Semmelweis realized that "cadaveric matter" which the student's scalpel had introduced into Kolletschka's blood stream had caused his colleague's fatal illness. And the similarities between the course of Kolletschka's disease and that of the women in his clinic led Semmelweis to the conclusion that his patients had died of the same kind of blood poisoning: he, his colleagues, and the medical students had been the carriers of the infectious material, for he and his associates used to come to the wards directly from performing dissections in the autopsy room, and examine the women in labor after only superficially washing their hands, which often retained a characteristic foul odor. Again, Semmelweis put his idea to a test. He reasoned that if he were right, then childbed fever could be prevented by chemically destroying the infectious material adhering to the hands. He therefore issued an order requiring all medical students to wash their hands in a solution of chlorinated lime before making an examination. The mortality from childbed fever promptly began to decrease, and for the year 1848 it fell to
3 1.27 per cent in the First Division, compared to 1.33 in the Second. In further support of his idea, or of his hypothesis, as we will also say, Semmelweis notes that it accounts for the fact that the mortality in the Second Division consistently was so much lower: the patients there were attended by midwives, whose training did not include anatomical instruction by dissection of cadavers. The hypothesis also explained the lower mortality among "street births": women who arrived with babies in arms were rarely examined after admission and thus had a better chance of escaping infection. Similarly, the hypothesis accounted for the fact that the victims of childbed fever among the newborn babies were all among those whose mothers had contracted the disease during labor; for then the infection could be transmitted to the baby before birth, through the common bloodstream of mother and child, whereas this was impossible when the mother remained healthy. Further clinical experiences soon led Semmelweis to broaden his hypothesis. On one occasion, for example, he and his associates, having carefully disinfected their hands, examined first a woman in labor who was suffering from a festering cervical cancer; then they proceeded to examine twelve other women in the same room, after only routine washing without renewed disinfection. Eleven of the twelve patients died of puerperal fever. Semmelweis concluded that childbed fever can be caused not only by cadaveric material, but also by "putrid matter derived from living organisms.
1. write the mortality rate of the first division(the room the interns managed) from 1844 to 1846. in addition, record the same information for the second division(the room the midwives managed), during the same period
First Division Second division
1844
1845
1846
2. Based on the above data: what problem was Semmelweis facing?
3. in an effort to solve the problem above, Semmeweis attempted to logically explain the reasons for the high mortality rare in the First Division
identify two ideas he examined, but in the end rejected.
4.what conclusion did a commision/committee identify as a possible cause of the high molity rate in the first division?
5. out of desperation, Semmelweis focused his attention on a priest who administered to spiritual needs of the patients. if you were Semmelweis what hypothesis would you construct regarding the priest and the disease afflicting his patients?
6. how did Semmelweis"test" his hypothesis? what was his conclusion regarding the priest and the spreading of the disease? what other desperate hypothesis did Semmelweis test and what was his conclusion?
7. what tragic event led to a new hypothesis regarding the cause of the disease (puerperal fever-child-bed fever)what was the new hypothesis?
8. Based on the hypothesis that Semmelweis formulated after his colleague died, he ordered the interns to wash their hands with a strong solution-chlorinated lime water.what happened to the mortality rate in the first division as a result of this procedure?
9.Why were the mortality rates in the second division consistently lower even though the midwives did not practicegood anti spectic techniques?why did the "street" births not develop child-bed fever?
10. Tragically, Dr Semmelweis inadvertently spread the disease (puerperal fever/child-fever) to 12 other women after examining a woman in labor suffering from a festering cervical cancer. As a consequence, his hypothesis that child-bed fever/puerperal fever is spread by"cadaveric material" had to be modified. what was the modified hypothesis? what logical "fallacy" had Semmelweis committed?
Explanation / Answer
Mortality rate division I II
1) 1844 8.2% 2.3%
1845 6.8% 2.0%
1846 11.4% 2.7%
2) Sammelweis was facing problem that large proportion of women who delivered babies in division I suffering from childbed fever whereas in second maternity devision of same hospital which accomodate as many women as first has lower rate of childbed fever or death rate than division I.
3) First idea was epidemic influence but he notes that why this influence effect I division not second.Then he notes that women admitted to division I living far from hospital and gave the birth to baby on street birth but still death rate of street birth was lower than the average of division 1.. Second idea was overcrowding, but he was rejected that idea because the crowding was heigher in division II. He reject two similiar conjecture that no difference in diet and general care of patient in both division.
4) The commission conclude that illness caused by injuries resulting from rough examination by medical students.
5) According to my hypothesis, preist visit doesnt affect the childbed fever in division I because if i have arrange the silent visit of priest to test my hypothesis then compare the death rate . I observed no lowering of death rate in division I which proves my hypothesis true.
6) Sammelweis persuaded the priest to come by roundabout without ringing the bell in order to reach sick chamber silently and unobserved but there was no change in mortality rate . Then sammelweis test the hypothesis which says in division I women delivered lying on their back whereas division II on their sides. He test the difference in procedure was significant or not. He used lateral position in division I but mortality rate was unaffected.
7) An accident in which his colleague received puncture wound in his finger from scalpal of medical student with whom he was performing an autopsy and died after illness during which he displayed same symptom that sammeweis observed in patient of childbed fever. From this incidence, he conclude that cadaveric matter in student scalpal introduce into patient bloodstream means patient died with some kind of blood poisoning.
8) As result of this procedure, mortility rate promptly began to decrease and in 1848, it fall to 1.27% as compare to 1.33% in division II.
9) The reason is midwives training not include anatomical instruction by dissection of cadavers thats why lower childbed illness in division II inspite of no good practice of antiseptic by midwives. Woman who arrived with babies in the arm after childbirth on street were rarely examined after admission so they easily escape from infection.
10) He modify his result that childbed fever not only caused by cadaveric material but also by putrid matter derived from living organism.He observed that without using good antiseptic procedure infection transferred to other women that examined by same scalpal.
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