No. 322 is a detachable wooden hand, with rigid fingers and movable thumb. A traction rod for opening the thumb with motion of shoulder is shown in the illustration; a web strap is buttoned to the upper end of the traction rod and passes over opposite shoulder, as shown in No. 326, page 70. Any motion of the shoulder that will draw on this rod will open the thumb, and when the tension is released a strong spring in the thumb brings it back in contact with the first finger. For single amputations there is little or no advantage in having this attachment put on; it necessarily requires more complicated and expensive mechanism, without any practical gain to the wearer. For double amputations something of this kind must be depended upon for assistance, and to obtain the greatest benefit from artificial arms, means similar to this for operating the movement of the thumb are absolutely required. One or more movable fingers in conjunction with the thumb may be operated in the same manner. PRICES, NO. 321 Including Plain Hook, Knife, Fork, and Brush Arm without hand, used as a peg arm; a hand may be subsequently applied $25.00 Arm with wooden or rubber hand, detachable at wrist 50.00 Arm with wooden hand and traction rod for opening thumb from shoulder 60.00 _Ball-and-Socket Wrist Joint_ No. 323 represents arm with ball-and-socket wrist joint for amputation below the elbow, but not suitable for an amputation near the wrist for the reason that the space in that locality is required for the mechanism of the joint. In the various uses to which an artificial hand may be put, a change in the position of the hand is often desirable; for example, in keeping a book or paper in position while being written upon with the sound hand, the artificial hand can be turned so that the tips of the fingers will rest upon and hold the article securely in place. In bringing the arm in front of the body the ball-and-socket joint admits of the hand being brought near to the body in a very easy, lifelike manner. In other positions desired the hand may be placed at the degree of flexion most convenient and helpful and that giving the most natural appearance. No. 332, on page 72, gives an illustration of the details of the joint. The forearm and attachment above the elbow are leather, supported with steel framework same as No. 321. Wooden hand with movable thumb is furnished with or without traction rod for opening thumb with shoulder movement, but no provision is made for the use of a hook or other implement in place of the hand. A rubber hand with palm socket for implements can be attached if preferred, but is somewhat heavier. For persons not employed in laborious occupations and who have no occasion to use a hook or similar implement, this style of arm is desirable; for others we would recommend No. 321. PRICES, NO. 323