With the salt I attended only to the inflection of the leaves, for it is far less efficient than the carbonate in causing aggregation, although considerably more potent in causing inflection. I experimented with half-minims (.0296 ml.) on the discs of fifty-two leaves, but will give only a few cases. A solution of one part to 109 of water was too strong, causing little inflection, and after 24 hrs. killing, or nearly killing, four out of six leaves which were thus tried; each of which received the 1/240 of a grain (or .27 mg.). A solution of one part to 218 of water acted most energetically, causing not only the tentacles of all the leaves, but the blades of some, to be strongly inflected. Fourteen leaves were tried with drops of a solution of one part to 875 of water, so that the disc of each received the 1/1920 of a grain (.0337 mg.). Of these leaves, seven were very strongly acted on, the edges being generally inflected; two were moderately acted on; and five not at all. I subsequently tried three of these latter five leaves with urine, saliva, and mucus, but they were only slightly affected; and this proves that they were not in an active condition. I mention this fact to show how necessary it is to experiment on several leaves. Two of the leaves, which were well inflected, re-expanded after 51 hrs. In the following experiment I happened to select very sensitive leaves. Half-minims of a solution of one part to 1094 of water (i.e. 1 gr. to 2 1/2 oz.) were placed on the discs of nine leaves, so that each received the 1/2400 of a grain (.027 mg.). Three of them had their tentacles strongly inflected and their blades curled inwards; five were slightly and somewhat doubtfully affected, having from three to eight of their exterior tentacles inflected: one leaf was not at all affected, yet was afterwards acted on by saliva. In six of these cases, a trace of action was perceptible in [page 149] 7 hrs., but the full effect was not produced until from 24 hrs. to 30 hrs. had elapsed. Two of the leaves, which were only slightly inflected, re-expanded after an additional interval of 19 hrs.