[The aging changes of biological variability (author's transl)]

1. Examples are given to justify the concept that biological variability is dependent on age. 2. It appears possible that the variability of fundamental parameters of those with a strong genetic fixation increases toward the middle of the life span and decreases again in the senium. 3. The variability of most variables increases with age. The more complex the variables, the greater the increase. 4. Originally unitary statistical populations may split up into several populations in the course of life. These will then require separate statistical treatment. 5. Our considerations seem to have some significance for the economical planning of tests and the selection of test persons.