ZOOLOGY AND BOTANY, MIOROSOOPYj ETC. 553 



The principal and most important feature of the apparatus consists 

 in making the object to be projected when the apparatus is to be used 

 as a Microscope, or as a megascope, the centre of all the projecting 

 and illuminating apparatus. The lantern-upright which carries the 

 projecting lens or Microscope, and the upright which carries the lens 

 and mirror for the vertical lantern, and the lantern itself, swing 

 around a common centre, which is placed exactly below the centre of 

 the stage on which the object rests. This enables the operator to 

 arrange, with the greatest facility, the relative positions of each of 

 these parts in any desiiable position in respect to the object. This 

 feature, it is claimed, has never before been accomplished, and makes 

 the lantern more complete, especially as a megascope. The lantern 

 and jet are movable, independently of each other, by means of racks 

 and pinions. By this arrangement the conjugate foci of the condenser 

 may be changed to suit low and high powers and narrow and wide 

 angle objectives, doing away with all secondary condensers and 

 accomplishing these adjustments better and with much greater facility. 

 The raising and lowering of the lantern is effected by a peculiarly 

 constructed clutch, which rigidly holds the instrument in an inclined 

 position. The instrument is packed in a truncated pyramidal box, 

 containing also the accessories, and forming at the same time a firm 

 stand for the lantern, on which it may be rotated when in use. 



In consideration of the fact that the instrument can be used for 

 such a variety of purposes for lecture illustrations, it cannot be 

 regarded as other than a marked improvement upon a similar class of 

 instruments hitherto used for such purposes. In the illustrating and 

 projecting of living forms alone, in conjunction with a number of 

 ingenious devices serving as live cages, Mr. Holman has done a real 

 service for the cause of education. While it is, perhaps, not possible 

 to enter into an elaborate or detailed study of any organic forms of 

 even a moderate degree of complexity, if projected only for a few 

 moments upon a screen, it is, nevertheless, a fact that the correct 

 likeness of such creatures so shown gives the beholder a far truer 

 appreciation of what the things are of which he reads in books than 

 he might possibly obtain elsewhere, provided the lecturer is able to 

 explain in a lucid manner, and unravel the complicated life-histories 

 of the living beings of which he displays enlarged images. In these 

 living animal or perhaps plant-pictures we have displayed two classes 

 of facts, namely, those of type and those of function. To the trained 

 biologist they call to mind the occult processes of growth and repro- 

 duction by which the forms become what we see them to be. 

 This implies that a wide range of data is to be considered: first, 

 there is the development and evolution of the form, together with 

 what this indicates as to its systematic relationship ; second, the 

 vital actions displayed involve the consideration of physiological pro- 

 cesses, and these again those internal quasi-chemical and physical 

 actions and interactions by means of which the creature is enabled 

 to maintain its existence and individuality. If such problems are not 

 worth elucidating, we may ask what others there are which are worthy 

 of elucidation '? The physiologist who solves the problem of the life- 



