One of Schwann's brothers had been a worker in metal, and Schwann himself had always shown a great interest in mechanical appliances. This hobby stood him in good stead in those days when laboratories did not contain all the intricate scientific apparatus and the facilities for experimentation so common now, with their workshop and skilled mechanics for the execution of designs. Many another worker in the biological sciences of that time owes his reputation to a similar mechanical skill. Experiments were impossible unless the investigator had the mechanical ingenuity to plan and the personal handiness to work out the details of appliances that might be necessary for experiments. It is told of Schwann that when Daguerre's discoveries in photography were announced, such was his interest in the new invention that he made a trip to Paris especially to learn the details of the method. Some daguerreotypes made by him according to the original directions of the inventor himself are still preserved by his family. Schwann's investigation of the respiration of the embryo in hens' eggs led to further studies of the embryo itself, and to the discovery that it was made up of cells. Later came the resolution of other tissues into cells. When, after his graduation as doctor in medicine, the post of assistant in anatomy at Berlin fell vacant, it was offered by Johann Müller to Schwann. The position did not carry much emolument with it. The salary was ten German thalers--_i.e._, about $7.50 per month--a pittance even in those days when the purchasing power of money was ever so much greater than now. His duties took up most of his time. The work was congenial, however, and Schwann remained here for five years. As Henle has said in his biographical sketch of {261} Schwann, in the _Archiv f. mikroskopische Anatomie_, just after his death in 1882: "Those were great days. The microscope had just been brought to such a state of perfection that it was available for accurate scientific observations. The mechanics of its manufacture had besides just been simplified to such a degree that its cost was not beyond the means of the enthusiastic student even of limited means. Any day a bit of animal tissue, shaved off with a scalpel or picked to pieces with a pair of needles or the finger-nails, might lead to important ground-breaking discoveries." For at that time almost everything as to the intimate composition of tissues was unknown. Discoveries were lying around loose, so to speak, waiting to be made. Schwann was not idle. The precious years at Berlin saw the discovery that many other tissues were composed of cells. The nuclei of the striped and unstriped muscles were found, and while the cellular character of these tissues was not demonstrated, their secret was more than suspected and hints provided for other workers that led very shortly to Kölliker's and Henle's discovery of muscle cells.