“Vitamin B12 deficiency causes tiredness, weakness, constipation, loss of appetite, weight loss, and megaloblastic anemia,” the National Institutes of Health says.

It is sufficiently conclusive for the pernicious nature of the case, "if only considerable portions but not the whole marrow, have lapsed into megaloblastic degeneration."

We can now say that the megaloblastic metamorphosis is not a purposeful process, and for the following reasons: 1.