PEOGRESS OF MICROSCOPICAL SCIENCE. 
239 
wrouglit sucli a revolution in the sciences on which medical practice 
is based. In this stage of his microscopic experience he will find a 
good treatise on the mechanism of the instrument useful, and such a 
treatise has just been provided for him by Dr. Pelletan. In a portable 
octavo volume, Dr. Pelletan describes in detail the construction of the 
microscope, and the application of micrography to the study of the 
organic tissues, whether of the vegetable or lower animal kingdoms, 
and illustrates the exposition by numerous engravings selected with 
good judgment. The style of the volume, like that of most French 
scientific treatises, is clear and even attractive." 
Do Plants Digest Animals ? — Mr. Darwin's inquiries on this point 
are well known to our readers. ' Nature,' however, gives us an account 
of an opposing idea. It states that an interesting addition to the 
literature of insectivorous i)lants is furnished by a reprint, by Casimir 
De Candolle, from the 'Archives des Sciences Physiques et JSTa- 
turelles,' " Sur la Structure et les Mouvements de Feuilles de Dioncea 
muscipula,'' With regard to the power of digestion, M. De Candolle 
comes to a conclusion opposed to that of Darwin, that the absorption 
of animal substances is not directly utilized by the leaves, and is not 
necessary to the development of the plant. He considers their ana- 
tomical structure favourable to the hypothesis that the movement of 
the two valves of the leaf results from variations of turgidity of the 
parenchyma of their upper surface. 
Contractile Vacuoles in the Vegetable Kingdom. — M. Maupas has 
published a recent paper on this subject. The contractile vacuole has 
been regarded as a characteristic of animality. But various recent 
facts are against this. M. Maupas describes contractile vacuoles he 
has found in macrospores of the algee, Microspora floccosa, Thuret, and 
Ulothrix variabilis, Kiitzing (both in Algeria). 
The Anatomy of the Ear is receiving considerable attention at 
this time. Two essayists are especially worthy of attention, Dr. Urban 
Pritchard, of King's College, and Dr. Victor Urbantschitch — a curious 
resemblance between the two names. And first of Dr. Urbantschitch. 
His paper is abstracted in a recent number of the ' Medical 
Eecord,' and it is stated as the result of the examination of the 
ossicles of fifty ears that the following may be taken as the average 
size of the different bones : 
Hammer. — The length of the hammer was on an average 
8 • 5 millimeters. The short process averaged 1 ' 6 millimeter in 
length. The long process was in an individual thirty years of age 
2-5 millimeters, and in one of twenty years 5*8 millimeters long. 
The manubrium, measured from the point of the short process to the 
lower end, ranged from 4*2 to 5*6 millimeters. The distance of the 
lower end of the manubrium from the periphery of the membrana 
tympani averaged in thirty-eight cases 3*5 millimeters from the 
inferior edge, 3 • 4 millimeters from the anterior border, and 4 • 6 milli- 
meters from the posterior border. 
Anvil. — The general distance of the upper end of the ambos-joint 
surface from the free end of the processus brevis was 5*3 millimeters, 
