belief that transfusion was the ‘new and completely convincing proof’ of the truth of circulation, who in contrast degraded him. The first recorded case of Denys' initial attempt at transfusion was between two small dogs, whom he intended to keep both alive, in contrast to the results obtained by the English. Although there was no real way to know if the recipient subject was effectively receiving blood as with the donor having blood removed, supposedly about nine ounces had been removed from the first and donated by the latter. According to his writings, one of the dogs suddenly weakened measurably, so much so that they stopped the experiment and began stitching up the dogs. One remained weak while the other maintained a more energetic and alert character, although Denys did note that the dog was not as ‘awake and gay’ as earlier. The physician then performed a sort of ‘control experiment’ with a third dog, of similar characteristics with those prior, to be assured that the effects recorded, regarding eye movement, food consumed and the weights of the subjects, were similar among them all and not due to other elements. Denys soon realized that blood transfusion represented the ticket to success all around Europe and to finally gain recognition in the Parisian elite. On March 9, 1667 he announced on the Journal des sçavans his intention to move his anatomical and experimental demonstrations regarding the potential of blood transfusion as a therapeutic tool to the public, basically establishing himself as the primary transfusionist of France, thus going against both the ideals of the Academy of Sciences of the Paris, Faculty of Medicine and those of Charles Perrault. Denys later moved his research to the private academy established by Henri Louis Habert de Montmor, who had seen in the physician an opportunity to take on both the English and the conservative French Academy of Sciences, established by Louis XIV, and consequently gain his own glory. Denys and Emmerez, with the new funds and supplies, progressed their experiments on dogs with various techniques and points of transfusion, they regarded them all as successful, as of the nineteen dogs recorded, none died. They also focused on interspecies transfusion, specifically in early April 1667 they started transfusions between calves and dogs, then moving on to sheep, cows, horses, and goats. Denys would go on to announce his successes to all the European scientific community