1. Contractures do not develop in the normal extremity of a cat, immobilized for as long as ninety days; but do develop in denervated muscles, if they are maintained in a shortened position for from forty-five to 105 days.

2. After primary suture of the sciatic nerve in cats, contractures occur in 84.2 per cent. of cases in one or more muscles below the knee, and after delayed suture in 100 per cent. of cases, after ninety days.

3. Contractures occur most frequently in the dorsiflexors of the foot of the cat after section and suture of the sciatic nerve. They are less severe, less frequent, and less persistent after primary suture than after delayed suture in untreated animals. Residual contractures are more frequent after delayed than after primary suture.

4. Massage and passive motion definitely decrease the frequency and severity of contractures of the dorsiflexors of the foot, which occur after primary suture. After delayed suture, this type of treatment seems only to retard the development of the peak frequency of contractures for forty-five days, but it undoubtedly decreases their severity.

5. The addition of electrotherapy to massage and passive motion delays the appearance of contractures for a longer period after primary suture than does the latter alone. Thus electrotherapy may have some beneficial influence in the early postoperative period. The longer the period of electrotherapy, the more closely do the frequency and severity of contractures approximate those in untreated animals. Electrotherapy favors the development of contractures in the unparalyzed antagonists of paralyzed muscles. It seems to retard the dissolution of contractures which occur after delayed suture.

6. Spontaneous movement of the animal after recovery of function can serve to dissipate a contracture, no matter what influences tend to preserve it.

7. Contractures are more frequent after section and suture of the sciatic nerve of cats, if the extremity is immobilized, than if the extremity is permitted to be free.