Call your doctor if your baby: 1  Is under 3 months old and has a temperature over 100.4 F. 2  Is over 3 months old and has a fever over 102 F. 3  Has a fever that lasts longer than 24 hours.  Has diarrhea, vomiting, or a rash with the 1  fever. Is very sleepy or looks sick.  Can't be soothed.
There is two main pigments found in human hair: Eumelanin has an oval or elliptical shape, which gives color to brown or black hair and is dark pigment. The higher the concentration of Eumelanin the darker the hair. Pheomelanin is what produces the color in blonde or red hair.
Scientists have put a lot of effort into investigating the cause of gray hair, and they believe they've gotten to the root of the problem. Hair gets its color from a pigment called melanin, which is produced by melanocyte cells in the hair follicles.