Those who have known and valued the Perry sepa­rators for their easy applicability and efficiency will appreciate the practicality of the improvements repre­sented in the six S. S. White Separators designed by Dr. W. I. Ferrier.

The theory in design and the principle of power application of the Perry separator are retained in the new instruments, but the limitations of the older forms have given way to a new and greater convenience and efficiency in the present separators.

Although each of these separators was designed for the particular application mentioned for it in the directions that follow, there will be instances when size and position of the teeth will call for the use of a sepa­rator in locations other than the special application mentioned for it. For example: Separators Nos. 1 and 2, in addition to separating incisors, can he used frequently between the cuspid and bicuspid, and between the bicuspids. Separator No. 3 can be used frequently be­tween the bicuspids, and No. 4 will find occasional use between the second bicuspid and first molar.

The good judgment of the operator should be exer­cised in these applications of the separators and the separator that fits the teeth and the arch best, with the least operative interference, should be used.

The fact that these separators have this wide range of application is a tribute to them. They will gain the space necessary for any type of filling operation, and for the examination of teeth for obscure cavities. They will also hold the rubber dam in place without the aid of ligatures on the teeth that are otherwise difficult to isolate, especially the lower incisors of young patients separate slowly.

AT NO TIME during tooth separation should the patient experience much discomfort. Do not attempt to obtain more space than is actually necessary at the commencement of the operation, because the spring of the separator will gradually give more space as the work progresses.

Experience has shown that these separators will give all the separation necessary for any type of operation and do this with little or no discomfort to the patient, no injury to the investing tissues, if they are applied according to the technique here outlined.

Under no circumstances should these separators be tightened to any appreciable extent before being blocked with compound chilled by compressed air, cold water, or both. This need not take over three minutes time.

Bring the jaws together by turning the bolts in the direc­tion opposite to that indicated by the arrows. Place the separator in the mouth, with the jaws at or near the gingival line, and estimate the distance the separator jaws can be opened and passed between the teeth without binding.

Remove the separator from the mouth and, by turn­ing the bolts in the direction indicated by the arrows with the fingers, open the separator to approximately the estimated distance mentioned in the preceding sen­tence.  Replace the separator in the mouth with the jaws at or near the gingival line and, with the wrench supplied for the purpose, turn the bolts in the direction indicated by the arrows until the four jaws find a seat upon the teeth far enough gingivally to avoid any interference.

Stabilize the separator by blocking with modeling compound, as illustrated. This gives the instrument so firm a seat upon the teeth that any type of work can be accomplished without the least disturbance to the separator.

From this point on the desired amount of separation can be obtained by making alternate half turns on each bolt, buccal and lingual. Caution - Make these half turns alternately, turning one bolt too many times before turning the other will lock the separator and injure the threads.