Ill 



perhaps but hardly profitable. To meet this idea the 

 speaker said that many are unaware that it is through 

 laborious study of the organism and development of the 

 lower animals, that data are obtained to interpret the more 

 complex organization of the human system. Facts ob- 

 tained by such study, as another has said, "furnish the 

 alphabet which we must learn in order to read the more 

 intricate compositions of nature." 



Thus, the human lungs present to the eye a very intri- 

 cate structure, difficult to explain. But the simpler lungs 

 of the frog, or the transparent lungs of the turtle, show 

 at a glance the general plan upon which the respiratory 

 organs of the higher animals are formed, viz. : that of 

 a sack or pouch, divided by partitions into numerous 

 chambers or cells, upon whose walls the minute blood 

 vessels form a mesh work, while these cells, by means of 

 a system of tubes, are open to the external air, which 

 they can alternately receive and discharge. 



So concerning the circulation of the blood through the 

 capillaries, the transparent web of the frog's foot under 

 the microscope has furnished demonstrations and taught 

 lessons which one might seek in vain in the human sys- 

 tem. 



One of the lowest forms of animal life is the micro- 

 scopic ainreba, an animal which appears like a mere struc- 

 tureless drop of jelly. Yet it has been seen to assume a 

 great variety of forms by alternate expansions and con- 

 tractions, to fold itself around and to take into its cavity 

 other animalcules or portions of plants, parts of which 

 it consumed, and other parts rejected as indigestible. 

 Curiously enough, the white corpuscles of the human 

 blood have been seen to imitate the amoeba so closely that 

 they have been named amosboid cells. They were first 

 studied by being removed from the circulation, and placed 



