Final answer:
The technique Hugh Logan used cannot be specifically determined from the given information, but the symptoms and diagnostic methods described suggest that John may have the influenza virus. Not getting the flu vaccine likely contributed to his susceptibility to the illness.
Step-by-step explanation:
Hugh Logan is not mentioned in the provided information, thus we cannot directly infer what his technique diagnoses without additional context. However, we can discuss the factors that might have contributed to John's illness, as presented in the second paragraph. John's presentation of symptoms and his regret at not getting a flu vaccine suggests he suspects he has the influenza virus. The physician's use of diagnostic tools like a stethoscope, chest radiography, and collecting blood, urine, and sputum samples indicates that they are assessing John's respiratory condition and looking for signs of infection, which could support or rule out the diagnosis of influenza. Multiple factors could have contributed to John's illness, including exposure to the influenza virus, possibly due to not receiving the flu vaccine and therefore lacking immunity. Additional details or patient history would be helpful to determine other contributing factors, such as pre-existing health conditions or environmental exposures.