94 Transactions of the 



observer to say whether the stomata of plants are closed or open, 

 a point at that time somewhat disputed. 



In two communications to the Society in 1842, he drew atten- 

 tion to the great assistance which chemistry might derive from the 

 use of the microscope, and goes on to state that a quantity of nitro- 

 gen, not exceeding the -j-jy^oth part of a grain, if existing as a 

 constituent of ammonia, may be detected with certainty by means of 

 this instrument, and pointed out that ammonia was a product of re- 

 spiration, a fact which did not obtain credence at the time, though 

 justice was subsequently done to him on this point by Dr. Kichard- 

 son, in his prize essay on the coagulation of the blood. 



In the second volume of the ' Transactions ' of the Society is 

 another paper he read, " On Animals of the Chalk still found in the 

 Living State in the Stomach of Oysters ; " referring to the apparent 

 identity between the fossil and living infusoria as of considerable 

 interest to the geologist, in showing that there is a connecting link 

 in the chain of organized beings of the same organic structure 

 from the secondary formation to the tertiary, and to preclude the 

 supposition that below the tertiary formation there are no recent 

 species. Eeasoning from the analogy of the recent oyster, the 

 author examined the fossil oysters of the Kimmeridge clay, in 

 which he met with similar forms as cosmiodiscus and others cor- 

 responding to those existing in the recent oyster, so as to leave 

 no doubt that they preserved the same beautiful mechanism, though 

 we cannot now detect it, for making a current to set in the direction 

 of the stomach, and he further infers that similar remains may be 

 found in still older formations. The result shows how much we 

 are indebted to the microscope for the confirmation of these views. 



At the British Association, June, 1845, he read a paper " On 

 Ciha and Cihary Currents of the Oyster," the object of which 

 was to show that the action of the ciliae attached to the tentacles 

 produces a strong current in the water, and thus that a number 

 of minute living organisms (infusoria) was brought within their 

 influence, and thereby affords a sufficient supply of food, thus com- 

 pensating the prehensile organs possessed by higher creatures ; and 

 although it was well known that the orifice of the alimentary canal 

 of the oyster was in the same manner fringed with cihae, it had not 

 been suggested, says Mr. Eeade, or proved by any natm-alist, tliat 

 the proper office of the ciliae was to bring to these Acej^halous 

 molluscs that food which they had not the power otherwise to seize. 



At the Exhibition of 1851 he exhibited an astronomical eye- 

 piece, of his own invention, called a solid eye-piece, which was 

 thought so highly of as to merit special mention. 



In 1861 he read a paper before the Koyal Microscopical Society, 

 '• On a New Hemispherical Condenser for the Microscope, and its 

 use in illustrating an important principle in Microscopic Illumina- 



