Questions 1. The data from the experiment Dr. Trudeau describes is shown below in Figure 1. Graphs like Figure 1 are called survival curves. Write a narration of the figure describing the results of the experiment. Explain why the rabbits are emaciated in groups 1 and 2. (Please note: What Dr. Trudeau called Experiments 1, 2, and 3 are more like what modern scientists would call treatment groups 1, 2, and 3, and that terminology is used in Figure 1.) Figure 1. Analyzing the Rabbit Island Experiment Percent Survival 100 80 60 40 20 Group 2 Group 3 Groun 1 रे
Experiment No. 1. Five rabbits were inoculated in the right lung and in the left side of the neck
with five minims of sterilized water in which was suspended a sufficient quantity of a pure
culture (third generation) of the tubercle bacillus to render the liquid quite perceptibly turbid
The needle of the Koch’s inoculating syringe was inserted subcutaneously on the left side of the
neck and in the third intercostal space to a depth of thirty millimetres on the right side. These
animals were then confined in a small box and put in a dark cellar. They were thus deprived of
light, fresh air and exercise and were also stinted in the quantity of food given them while being
themselves artificially infected with the tubercle bacillus.
Experiment No. 2. Five healthy rabbits were placed under the following conditions: A fresh hole
about ten feet deep was dug in the middle of a field, and the animals having been confined in a
small box with high sides but no top, were lowered to the bottom of this pit, the mouth of
which was then covered with boards and fresh earth. Through this covering a small trap door
was cut which was only opened long enough each day to allow of the food, consisting of a small
potato to each rabbit, being thrown to the animals. So damp was the ground at the bottom of
this pit that the box in which the rabbits were confined was constantly wet. Thus these animals
were deprived of light, fresh air, and exercise, furnished with but a scanty supply of food while
breathing a chill and damp atmosphere, though free from disease themselves and removed as
far as possible from any accidental source of bacterial infection.
Experiment No. 3. Five rabbits having been inoculated in precisely the same manner as the
animals in the first experiment, were at once turned loose on a small island in June, 1886. It
would be difficult to imagine conditions better suited to stimulate the vitality of these animals
to the highest point than were here provided. They lived all the time in the sunshine and fresh
air, and soon acquired the habit of constant motion so common in wild animals. The grass and
green shrubs on the island afforded all the fresh food necessary and in addition they were daily
provided with an abundant supply of vegetables. Thus, while artificially infected themselves
they were placed in the midst of conditions well adapted to stimulate their vital powers to the
highest point attainable.
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