It is in fact an essential character of the extensibility of almost all the cellular system in which the layers and consequently the cells are united, to have the power always of being put suddenly in action and in an instantaneous manner. We have an example of this kind of extension in emphysemas artificially produced, which make this texture go suddenly from a state of perfect contraction to the greatest extension of which it is capable. The artificial injection of different fluids exhibits the same phenomenon. We observe it also as a consequence of fractures, and contusions of the limbs, in which we sometimes see enormous swellings appear in a manner almost as sudden. The cellular texture is evidently the seat of those swellings which take place in that texture which is sub-cutaneous, and not in that subjacent to the aponeuroses, because the extensibility of these membranes not being capable of being suddenly put into action, resists all dilatation that is not gradually made. Many other organs, as the tendons, the cartilages, the bones, &c. though possessing, like the cellular texture, extensibility of texture, differ from it like the aponeuroses, in the impossibility of being suddenly distended. In general, the softness of the primitive structure appears to have great influence upon this modification of extensibility. The cellular texture, extended too far, becomes at first very thin, and then breaks. In a natural state, no motion of the economy is capable of being carried so far as to occasion this; for example, I have remarked in regard to cellular texture taken from the axilla, that it is necessary to extend it at least three times as far as it is in the elevation of the arm, to produce this phenomenon. Besides, what opposes also this rupture, is a kind of locomotion of which it is capable; so that if too violently drawn, it displaces that which is contiguous to it, draws it towards itself, and thus becomes less stretched. We see this phenomenon in a remarkable manner in the swellings of the testicle, in large hydrocele. Then all the surrounding texture, that of the lower part of the abdomen, the top of the thighs, and the perinæum, drawn by that which immediately covers the tumour, is thus brought also upon it. I have observed that the inflamed cellular texture loses in part this property, and that upon the dead body it breaks with great ease. This takes place also in different indurations of which it is the seat. For example, that surrounding a cancerous womb, being swelled, loses the capacity of being extended; it is brittle, if I may be allowed to use the word; the least effort is sufficient to break it. This fact is uniform in all cancerous affections, somewhat advanced, of the womb and in those of many other organs. _Contractility._