There are numerous medical situations involving deficiencies of living tissue and where increase of living tissue mass is desired. Methods are described wherein a configured, shell-like device that is capable of being penetrated by living cells and tissues, is implanted into the body of a mammal in such a way as to establish a space, the space being at least partly, bounded by the device. The configuration of the device is such that the configuration of the established space is essentially the same as the configuration of living tissue that is desired for treatment of the tissue deficiency. At least one tissue stimulating molecular substance is placed within the established space for the purpose of stimulating the growth of desired living tissue within the established space. A kit for the generation of desired living tissue, comprised of the components mentioned above, is also disclosed.