III. MEASUREMENT. 793 



The first (Fig. 1., Pamphlet) is intended to fit round the head, and to trace 

 its principal circumference. 



The second (Fig. 2) may be fitted lengthwise, cro sswise, or in any other 

 direction required. 



The principal use of the third (Fig. 3) is to determine the profile of the 

 face. 



For further particulars, see the monograph " LeKephalograph," by Pro- 

 fessor Harting. 



3723. A Balance for Physiological and Clinical Pur- 

 poses, on polished oak. 



The Brandenburg Balance Manufactory -, Messrs. Kuhtz 

 8? Co., Brandenburg on the Havel. 



These balances and weights are being extensively used in all scientific 

 schools, and especially by practical physicians. They are available and 

 almost indispensable for the investigation of the disturbances of nutrition in 

 childhood ; for the estimation of the loss or gain of weight by the body during 

 the course of lung disease, diabetes mellitus, acute diseases, &c. ; for the study 

 of the normal growth of the body ; and for pathological and anatomical 

 investigations in which weighings are required. 



The balance carries 150 kilogrammes and turns with 0*25 grm. By means 

 of the pointer attached to the beam and the ivory scale, a still smaller difference 

 in weight can be detected. 



3724. Set of Iron and Brass Weights, accurately 

 adjusted. 



The Brandenburg Balance Manufactory , Messrs. Kuhtz 

 fy Co., Brandenburg on the Havel. 



3732. Manometer, with movable level of the mercury. 



Physiological Institution, Prague. 



The above is a quicksilver manometer, the legs of which communicate with 

 a vessel containing mercury ; the bottom can be lowered or raised by means of 

 a screw. The manometer allows, among other things, a very quick measure- 

 ment of the pressure of the saliva, during secretion. 



PROFESSOR A. CRUM BROWN'S PREPARATIONS AND APPARATUS. 



3733. Skull with internal ear prepared for the measurement 

 of the relative position of the planes in which the semicircular canals 

 are situated. 



Two saw-draughts are cut through the outer table of the skull, forming a large 

 angle with one another. These saw-draughts pass through the mastoid part 

 of the temporal bone, and are continued into the neighbouring parts of the 

 skull ; two pieces of steel plate are cut so as to fit into the saw-draughts, and 

 the position in which they fit indicated by marks on the plates and on the 

 mastoid bone. The greater part of the mastoid and the whole of the petrous 

 portion are thus sawn out, and the steel plates fixed to the portion of bone 

 thus removed. This portion can now be replaced exactly in situ by placing 

 the ends of the steel plates into the portions of the saw-draught remaining on 

 the skull. The remaining portion of bone is now plunged into a bath of 

 fusible metal, and placed under the receiver of an air pump. On exhausting, 

 bubbles of air escape from the cavities in the bone, and on re-admitting air 

 these cavities are filled with fusible metal. By repeating this operation ten or 



