42 ANIMAL AND VEGETABLE TISSUES. 



magnifying powers, to be actually vegetables. In 

 some instances, the microscope reveals a broad dis- 

 tinction between an animal and a vegetable tissue, 

 but in others, it is diminished until any difference 

 is scarcely, if at all, perceptible. A further study 

 of the different tissues of organic bodies will doubt- 

 less add important facts to the knowledge already 

 acquired. 



Nor should it be overlooked, that "it has been 

 recently stated, and apparently upon good foun- 

 dation," as Professor T. R. Jones remarks, " that 

 there are organized forms, that are vegetables at one 

 period of their existence, and animals at another. 

 Many of the conferva," consisting of simple tubular 

 jointed species inhabiting fresh water, " for example, 

 are equally claimed by zoologists and botanists ; 

 and some among them are said to be possessed of 

 locomotion in one stage of their growth, while in 

 another they are fixed and motionless. So nearly, 

 then, do the animal and vegetable worlds approxi- 

 mate, remote and separate as they appear to be 

 when examined only in their typical forms. Light 

 and darkness are distinct from each other, and no 

 one possessed of eyesight would be in danger of 

 confounding night with day ; yet he who looking 

 upon the evening sky would attempt to point out 

 precisely the line of separation between the parting 

 day and the approaching night, would have a diffi- 

 cult task to perform. Thus is it with the physiologist 

 who endeavours to draw the boundary between 



