Carpenter on the Microscope. 351 



There is another question on which, microscopists would 

 have been glad of somewhat more information. We allude to 

 the practical value of such powers as Messrs. Powell and Lea- 

 land's l-25th. Dr. Carpenter has only slightly modified the 

 expressions previously applied to the l-16th, that it is " ques- 

 tionable whether anything is really gained thereby/' a dictum 

 that is not confirmed by a subsequent statement that the 

 l-25th showed a certain movement in a plant cell not visible with 

 other means. This power was likewise advantageously em- 

 ployed in the recent researches into the peripheral nerves made 

 by Mr. Lionel Beale. The use of such high objectives must 

 necessarily be very limited, and their employment without great 

 judgment would only help to mislead. They may, however, be 

 the means of explaining many particulars of extremely minute 

 structure, and of elucidating the cause of movements like those 

 of diatoms or the closterium, which yet remain a puzzle to be 

 resolved. 



Among the important additions to the present issue, we 

 notice an account of M. Balbiani's discoveries on the reproduc- 

 tion of Infusoria — the first comprehensive view of which was 

 given to the English reader in our own pages ; a complete re- 

 modelling of the chapter on Diatoms, with explanations of 

 the classification recommended by Mr. Ralfs ; a collection of 

 recently ascertained facts concerning the generation of the 

 Volvox globator, showing that it forms no exception to the 

 general rule, that bisexual propagation is- a fact that occurs at 

 some period of the history of an organized being. Moreover 

 the account of the Rhizopoda has been re-written, and that of 

 the Foraminifera enlarged and made to contain an exposition 

 of the new views which have resulted from the labours of Dr. 

 Carpenter, Mr. Parker, and Mr. Rupert Jones. There are also 

 other additions of importance, including Mr. Rainey's remark- 

 able discoveries of "Molecular Coalescence," of which drawings 

 are given. These researches tend to connect purely physical 

 with what are called vital processes, and Dr. Carpenter's re- 

 marks upon them will stimulate other inquirers to enter upon 

 the path which has been so ably opened before them. Mr» 

 Rainey brings about " a slow decomposition of the salts of lime 

 contained in gum by the agency of sub-carbonate of potash. 

 The result is the formation of spheroidal concretions of carbonate 

 of lime, which progressively increase in diameter at the expense 

 of an amorphous deposit which at first intervenes between 

 them; two such spherules sometimes coalescing to produce 

 dumb-bells, while the coalescence of a large number gives rise 

 to a mulberry-like body." Similar concretionary spherules, 

 Dr. Carpenter says, occur in the skin of the shrimp, in imper- 

 fect layers of the shell of mollusca, and they appear to form 



