[The sphygmograph in England (1860-1900). How a physiological instrument entered medicine]

Stuart Blume, in his 1992 book Insight and industry. On the dynamics of technological change in medicine, designed his model for the development of twentieth century imaging devices. The development of instruments, according to Blume, is divided into four stages: exploration; development; diffusion, evaluation and assessment; and feedback. The central question in this article is whether Blume's model can be applied to the nineteenth century context of the increasing use of diagnostic instruments, related to the 'scientification' of medicine. A case study of the sphygmograph shows that in the nineteenth century a considerable overlap in time can be found between the different stages. Nevertheless, most of the characteristics of these stages do correspond to the nineteenth century situation. Therefore it is suggested to replace the stages model with a spiraled model, in which four elements of development play a part: new ideas, experiments, construction of prototypes and publication of the results. Besides, the different whirls should not be subdivided according to the disciplines in which the technique was used, but with reference to the amount of specialisation occuring around the instrument. The development would then be described from an amateur's workshop to respectively an experimental physiological laboratory, an instrumentmaker's workshop, and an experimental medical practitioner. Subsequently the level changes to that of an established laboratory, a commercial producer and a more or less specialised medical practice. Through these stages other long-term constituent processes take place. Advantage of this model is that its basic categories--ideas, experiments, construction of prototypes, publication of results--can be extended with subcategories at any level if the social situation demands this.