What chemicals can a live human body supply?

Question

I know the obvious-- salts washed from the skin and allowed to evaporate (mixed sodium and potassium salts, IIRC), impure ammonia from the urine, impure hydrochloric acid from the gastric juice, and methane from the obvious source.

Any others? I mean, any others not requiring a great deal of extraction or processing; I'm not talking about getting iron out of the blood.

I'm working on a story involving people discovering chemistry (not alchemy, please!) and having extremely limited resources with which to work. Please do not refer me to internet references or textbooks, because my characters do not have access to them. Persons who disregard this will obviously not get Best Answer!

Thanks to all who answer

Answer 1

I guess it depends on how invasive you want to be. You can draw blood and isolate insulin and other hormones from the human body, you can invasively get bile salts, it is possible to get a particular clone of specific antibodies to a specific antigen by immunizing someone with the antigen anf drawing blood and purifying the antibodies. You may even be able to extract and purify enkephalins, interleukin, and other proteins (although they are in very small amounts). Hormones such as growth hormone, FSH, LH, Thyroid stimulating hormone, T3, T4, and calcitonin can theoretically be harvested from the human body. You can harvest iron from red blood cells. Other minerals include potassium, magnesium, manganese, etc.