=The nose-piece= has now become an almost indispensable part of a working microscope. It can, however, be used to best advantage only on such stands as are provided with a coarse adjustment by rack and pinion. Aside from the advantage derived from the rapid changing of objectives, which it permits, it is so accurately made and centered as to materially facilitate the focussing of the various objectives. It is only necessary to focus with the fine adjustment to obtain a view of the same microscope field which had been under observation before the change was made. As it is necessary for this purpose that the objectives should be accurately adjusted to the nose-piece, it is very desirable that in ordering an instrument its nose-piece should be ordered at the same time if one is to be used, as subsequent ordering may necessitate the return of the stand and objectives to us. =Stands A, I, Ia, Ib, II, IIa, IIb and III= are those which are best suited to fine microscopical investigations. Among them the physician and bacteriologist will find an instrument entirely suited to his particular needs. =Stand III= is now provided with rack and pinion adjustment. =Stands IV and V= are small instruments, which serve nevertheless many purposes where the more elaborate outfits are unnecessary. They make excellent laboratory stands for elementary courses in microscopy. In =Stands IV and V= the coarse adjustment is by means of sliding tube. They are all provided with fine adjustment by micrometer screw. =Stand VI= is provided with rack and pinion adjustment only. It has a large stage, and is particularly intended for searching for trichinae and for similar examinations where a very strong durable stand is desired and where the use of high power objectives is unnecessary. It may also be useful as an auxiliary stand for purposes of demonstration in laboratories. =Stands III, IV, V, VI= have no joint for inclining the body. =Stands A, I, Ia, Ib, II, IIa, IIb, III, IV= have mahogany cases (provided with a nickelled handle), in which the microscopes stand. =Stands V and VI= are laid in mahogany boxes. These cases are furnished with the microscopes without extra charge, when a =complete outfit=, including oculars and objectives is purchased. Object clamps and test objects accompany every microscope. The objectives to Stands A, I, Ia, Ib, II, IIa, IIb are in brass boxes; those for Stands III, IV, V and VI are in morocco cases. =Illuminating Apparatus.= =a. Illuminating Apparatus of Stands A and I.= The apparatus includes the following parts: Cylinder iris diaphragm. Swing-out condenser. Diaphragm carrier with iris diaphragm. Plane and concave mirror. The cylinder iris diaphragm comes into play when the condenser is swung out of position. To do this the diaphragm carrier is turned to the side as shown in the diagram, a small knob is pressed, which liberates the condenser, and the latter is swung out to the side.