[Natural family planning: ovulation method after Billings (author's transl)]. / Natürliche Familienplanung: Die Ovulationsmethode nach Billings.

PIP: During the last decade, the World Health Organization has paid increasing attention to some reliable methods of birth control based on periodic abstinence. There are 2 main methods of natural family planning--the Sympto-Thermal method and the Billings Ovulation method. The latter is explained in this paper. Its scientific basis, use, effectiveness, and importance as a birth control method as well as for understanding certain types of infertility are discussed. (author's)^ieng

Single cilia in the articular cartilage of the cat.

Single cilia (SC) in the articular cartilage of the cat are described with regard to structure, frequency and intracellular location. Comparison is made with their occurrence in the cartilage of other species or in other tissues; special consideration is given to their developmental stages. In the 1-year-old cat examined, about 20% of the cells showed SC with a predominantly intracellular course and some of them did not reach the extracellular space at all. Cross-sections of the proximal region of SC reveal the familiary 9+0 pattern; towards the distal end, the number of doublets and the diameter of the shaft are decreasing. It is concluded that most of the SC encountered are undergoing involution.