The chloride concentration of saliva and sweat in infancy

Summary 1. The chloride concentration of the saliva at birth is high in both premature and term infants and falls rapidly during the first week of life. 2. The salivary chloride concentration continues to fall at a much slower rate during the first two years of life and then appears to stabilize through 10 years of age. 3. On the other hand, the chloride concentration of sweat is low at birth, even in the premature infant. 4. The importance of these observations in the diagnosis of cystic fibrosis of the pancreas is pointed out. 5. The possible relation of salivary chloride concentration to the presence of the staphylococcus in the nose and throat is discussed.