Final answer:
Dr. Bourdette is not directly mentioned in the provided contexts, which discuss Nazi medical experiments on hypothermia at Dachau and natural physiological responses to extreme cold. There seems to be a mix-up in the question, as Dr. Bourdette does not correspond to historical references within the excerpts.
Step-by-step explanation:
The question appears to be broadly related to the histories of human survival and responses to extreme cold and medical experimentation. However, no direct mention is made of an individual named Dr. Bourdette within the context of these historical texts, leading to an ambiguity in the question's reference. Taking into consideration the provided excerpts, particularly the one about a Nazi medical experiment conducted at Dachau concentration camp and overseen by SS doctor Sigmund Rascher, the question could be interpreted as inquiring about unethical human experimentation during World War II. Victims, such as those in Dachau, were subjected to freezing conditions to study hypothermia, which often resulted in death or severe injury.
Other narratives presented involve depictions of individuals facing fatal cold, such as in Jack London's story, where a man's extremities begin to freeze when he stops moving in extreme cold conditions. The narrative captures the physiological response to severe cold exposure, describing how the body's blood withdraws from the extremities to protect core organs, leading to frostbite and eventual death if not properly addressed. This response is an involuntary and natural reaction to the cold, in stark contrast to the forced and inhumane experiments carried out by Rascher.