No. 7 tube containing some of the wood of a branch from which the grapes had been detached. In the course of the following days fermentation took place in 4, 5, and 7. In this case three out of four of the uncrushed grapes did not cause the must in which they were placed to ferment; whilst the same must fermented in one of the two tubes containing wood of the branch, and in the other remained unchanged; and, lastly, the tube containing the woody peduncles of the bunch fermented. We have already remarked that it was more particularly the wood of the bunch that was charged with germs of ferment. The truth of this assertion was proved by the following series of experiments. On October 2nd, 1875, we charged at the vineyard twenty-four tubes, all of which were about a third filled with pure must that had been previously boiled. Nos. 1, 2, 3, 4, 5, and 6 tubes containing one crushed grape. No. 7 tube containing two crushed grapes. No. 8 tube containing one crushed grape. Nos. 9, 10, 11, and 12 tubes containing some wood of a branch of the vine. Nos. 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, and 24 tubes containing a fragment of the wood of a bunch from which the grapes had all been detached and removed. In the course of the following days some of these tubes began to ferment; but in others only fungoid mycelia were visible. On October 7th the following tubes were fermenting: the second of the first eight containing whole or crushed grapes; not one of the four that contained wood of the branches; whilst, on the other hand, of the tubes containing wood of the bunches, 15, 17, 20, 21, 22, 23, and 24 were all in full fermentation. In short, fermentation, and therefore germs of yeast, were present in one single tube out of eight containing grapes; in none of the four tubes containing wood of the vine branch; but in seven out of the dozen containing wood of the bunches. There was no subsequent change in the number of tubes that fermented. The same day that we arranged this series of tubes we prepared twenty-four other similar ones, using the _wood of bunches preserved from the vintage of the preceding year_. Not one of these twenty-four tubes showed the least sign of fermentation, although they contained grape juice in presence of the wood of the bunches; this was a further confirmation of the sterility of the germs of ferment in the case of bunches of grapes preserved for a sufficient time. The next question to be considered was, what length of time after the vintage do the germs on the surface of the woody part of bunches of grapes preserve the faculty of producing yeast? The following experiments were undertaken to determine this point.