1896 THE MICROSCOPE. 41 



silica and lime iu it. Happening recently to examine some 

 slides of English Upper Cretaceous, some Melbourn rock 

 chalk, they were struck with the resemblance of the 

 spherical bodies in it to the general appearance presented 

 by calcified and semi-destroyed Radiolaria in some of 

 the Barbados rocks. Tlien they confirmed these splicri- 

 cal bodies to be Radiolaria. They submitted some of the 

 slides to Dr. Hinde, the well-known geologist, and he 

 confirmed their observation and thought the spherical 

 bodies were Radiolaria if they were not Bacillariacese, 

 Coscinodiscus, but those were not spherical but circular. 

 The examination of the spherical bodies showed the 

 fading of the spheres away into calcite, gradually some- 

 times granular and sometimes crystalline the silica 

 being removed and replaced by carbonate of lime. This 

 would occur with colloid silica and not with crystalline 

 silica. From this they reasoned that the Radiolaria were 

 removed and replaced by casts of calcite, and why may 

 not Diatoms also be removed and replaced by the casts of 

 carbonate of lime which in turn would be dissolved by the 

 acids used to clean the earth. It seems reasonable. Re- 

 member that the shells of Diatoms are not crystalline 

 silica, which is insoluble, but colloid silica which is readily 

 soluble in natural water. They are also made up of 

 clay, silicate of aluminium which is also soluble and cel- 

 lulose, also readily soluble. In Infusorial earth the 

 shells of Diatoms are made of clay. 



Botany at Cornell. — Associate Professor G. F. Atkinson has 

 been made Professor of Botany. Prof. W. W. Rowlee has be- 

 come the first assistant professor. E. J. Durand and K. M. 

 Wiegand are instructors. In accordance with tlie rearrange- 

 ment the following courses will be given the coming year. 



I. Comparative Morphology and Embryology. Mycology and 

 Algology by Prof. Atkinson and Instructor Durand. 



II. Comparative Histology, Systematic Botany and Dendrol- 

 ogy by Prof. Rowlee and Instructor Wiegand. 



