Quantitative Untersuchungen über das postnatale Wachstum von Rattus norvegicus Berkenhout unter normalen und statisch veränderten Bedingungen

Abstract

Growth is subject to a multitude of environmental factors affecting the shape of the growing organism. The close connection between structure and function is particularly impressive in the effects of statics on the growth process. The purpose of.this series of publications was to investigate the postnatal growth of Rattus norvegicus Berkenhout, taken from a Wistar line after conditions with regard to statics had been changed. Rats with amputated front extremities served as experimental animals. The animals were observed from the 40th to the 130th day after amputation. Great importance was attached to biomathematical evaluation methods for these investigations. For this purpose, quantitative analyses were performed with regard to body weight (part I of this series), thoracic organs (part II), abdominal organs (parts III and IV) and the organs of the urogenital system (part V). In this concluding part of the series, the animal is presented from the biological standpoint. The locomotion of the rats after amputation is characterised by a waddling motion with the body almost erect, and a hopping motion akin to that of the kangaroo. No differences were established between the controls and the experimental animals with regard to behaviour or life expectancy.This part of the series closes with an appraisal of the mathematical approach for the interpretation of the growth processes. The model incorporating 2nd order homogeneous differential equations proved to be practical from biological aspects.