144 Chronicles of Science. [Jan., 



Diatom Markings and Podura-scale Markings. — The Eev. 

 J. B. Eeade, by the use of a very admirable reflecting medium, 

 viz. a prism — constructed by Mr. Highley, of London — has been 

 able to demonstrate satisfactorily that the so-called hexagonal 

 markings of diatoms are, as Mr. Wenham had previously urged 

 from investigating splintered bits of diatom-valves, simply hemi- 

 spherical close-set tubercles. Dr. Eoyston Pigott, of Halifax, had, 

 curiously enough a little before Mr. Eeade, come to the conclusion 

 that the well-known markings of the Podura-scale are caused by 

 a series of spherical " beads " placed in the substance of the scale, 

 which so act on the light as to produce the effect known to all 

 microscopists. Dr. Koyston Pigott has examined the subject with 

 exceeding care, having had a y^th especially constructed for his 

 use, and availing himself of great mathematical knowledge in dis- 

 cussing the optical problems involved. 



Literature. — The reader is reminded of the ' Eecord of Zoo- 

 logical Literature', part of which is now ready, and which to 

 increase its usefulness is now brought out in three separate volumes, 

 so that those interested in a special department may obtain a com- 

 plete and reliable record of what has been written concerning 

 it during 1868, without being encumbered by other matter. — 

 M. Pollen, with the aid of several illustrious Dutch professors of 

 Natural History, is publishing at Leyden an elaborate work on 

 1 The Fauna of Madagascar and the neighbouring Islands,' where 

 he spent some years exploring and collecting. — A new work 

 by Mr. Darwin, ' On Man,' is stated by ' The Academy ' to be in 

 preparation. 



Memorial to Dr. Sliarpey.—k physiological laboratory and 

 scholarship and a portrait and bust of Dr. Sharpey are now being 

 subscribed for by old and present students of University College, 

 London, and by others interested in physiological research, and 

 who value the teaching and influence of Dr. Sharpey in this 

 country ; the object of the subscription being to do honour to 

 Dr. Sharpey, and to form a species of testimonial or memorial 

 to him. There is not in England a single laboratory of experi- 

 mental physiology properly worked and used for the education of 

 students. It is to be hoped that the proposed Sharpey laboratory 

 may form an example to be followed elsewhere. A distinguished 

 German physiologist lately observed upon the strangeness of the 

 fact, that in England we produce absolutely no physiologists in 

 the strict sense. This may be due to the want of laboratories, 

 which are provided by the State in other countries. 



