Knowing, as we do, that Luther developed his doctrine of the Lord's Supper gradually[7] and under stress of much opposition from all sides, it is interesting for us to note the stage of that development which this treatise represents. We may, therefore, inquire how he stood at this time on the question of the Real Presence. This question is answered under the fourth point of section 12. The true presence of the body and blood cannot be more clearly admitted than is done in sections 11 and 12 of this treatise. We can safely say that there never was a time when Luther was uncertain on this point. The point of view from which he discusses the significance of the sacrament in the Sermon von dem hochwürdigen Sacrament (1519) has sometimes been cited to the contrary, but even in this Sermon, with its emphasis upon the spiritual body of Christ, of which even those may be partakers whom the pope might exclude from the external communion, he speaks of the bread and wine as being changed into the Lord's "true, natural flesh" and into His "natural, true blood," [8] which shows that Luther at that time, nine months before the appearance of this Treatise on the New Testament, still held even to the conception of transubstantiation. He cannot, therefore, have had doubts about the Real Presence. In view, however, of the rapid development of Luther's doctrinal conceptions, we might further ask: Did Luther still retain his belief in transubstantiation at the time when he wrote the Treatise on the New Testament? At the beginning of October in this same year, in his Babylonian Captivity, Luther comes out for the first time with an attack on this Roman doctrine. He regards it as a mere human opinion, which one may accept or not accept, and clearly inclines to the belief that after consecration not only the form (Gestalt; species), but also the substance of bread and wine is still present.[9] In the Sermon von dem hochwürdigen Sacrament he spoke of the "shape and form of the bread"; in the present treatise he chooses the expression: "His own true flesh and blood under the bread and wine" (sec. 12). This would soon to indicate that in this writing he already holds the opinion which he soon afterward expressed in the Babylonian Captivity. But while he believed in the real presence of Christ's "own true flesh and blood," this body of Christ he regards—at this time, when he has not yet had to meet the spiritualistic interpretation of the Sacramentarians—as a sign only, a thing signifying the blessing of the sacrament, which is forgiveness of sins and life eternal (sec 10). Exactly the same view is expressed in the Sermon of 1519[10]. "Luther does not yet speak of 'any value which this body, sacramentally imparted, is supposed to have in and of itself.'" [11]