CONTINUITY. 203 



and mechanical forge, and find our present resources exhausted, 

 the more we can invent new modes of conversion of forces, the 

 more prospect we have of practically supplying such want. It 

 is but a month from this time that the greatest triumph of 

 force-conversion has been attained. The chemical action 

 generated by a little salt-water on a few pieces of zinc will 

 now enable us to converse with inhabitants of the opposite 

 hemisphere of this planet, and 



' Put a girdle round about the earth in forty minutes.' 

 The Atlantic Telegraph is an accomplished fact. 



In Physiology very considerable strides are being made by 

 studying the relation of organised bodies to external forces ; 

 and this branch of enquiry has been promoted by the labours 

 of Carpenter, Bence Jones, Playfair, E. Smith, Frankland, and 

 others. Vegetables acted on by light and heat decompose 

 water, ammonia, and carbonic acid, and transform them into, 

 among other substances, oxalate of lime, lactic acid, starch, 

 sugar, stearine, urea, and ultimately albumen ; while the living 

 animal reverses the process, as does vegetable decay, and pro- 

 duces from albumen, urea, stearine, .sugar, starch, lactic acid, 

 oxalate of lime, and ultimately ammonia, water, and carbonic 

 acid. 



As moreover, heat and light are absorbed or converted in 

 forming the synthetic processes going on in the vegetable, so 

 conversely heat and sometimes light is given off by the living 

 animal ; but it must not be forgotten that the line of demar- 

 cation between a vegetable and an animal is difficult to draw, 

 that there are no single attributes which are peculiar to either, 

 and that it is only by a number of characteristics that either 

 can be defined. 



The series of processes above given may be simulated by 

 the chemist in his laboratory ; and the amount of labour 

 which a man has undergone in the course of twenty- four hours 

 may be approximately arrived at by an examination of the 

 chemical changes which have taken place in his body ; changed 

 forms in matter indicating the anterior exercise of dynamical 

 force. That muscular action is produced or supported by 



