Final answer:
The cure for scurvy was not universally adopted despite being known due to perishability of fruits, skepticism, and supply and storage issues. Lind's experiment was a controlled trial to prove the efficacy of citrus fruits in scurvy prevention, but faced limitations such as individual health variables. Cider, containing some vitamin C, also led to improvements, showing the importance of this vitamin in combating scurvy.
Step-by-step explanation:
Even when the cure for scurvy was known in Europe, there were several reasons why it wasn't always used. Scurvy is caused by a deficiency in vitamin C, and James Lind's experiments showed that citrus fruits could prevent and treat the disease. However, the implementation of this knowledge faced obstacles such as the perishability of citrus fruits, skepticism about the treatment within the medical community, and the slow spread of knowledge across seafaring and medical communities. Additionally, challenges in efficient supply and storage for long sea voyages also hindered widespread adoption.
Lind's experiment was groundbreaking in its approach; he kept the sailors' diets the same except for the daily supplement to ensure that any differences in the sailors' health could be attributed to the supplements they received. This method is a fundamental principle of controlled experiments. Other factors that could have affected the outcome of the experiment include the individual health conditions of the sailors, environmental factors, and possible variations in the way each sailor's body absorbed nutrients.
The sailors who drank cider exhibited some improvement likely due to cider's vitamin C content, though it was less effective than citrus fruits. Cider was included in the regiment during the experiment and showed that not only citrus fruits but also other sources of vitamin C could have a positive effect on scurvy symptoms.