Tke Physics of Respiration 



CHARLES M. BREDER, JR. 



MOOR OR BLACK TELESCOPE BROADTAIL GOLDFISH 



Owned kvp Hartman of Philadelphia 



~~~* 



I read with interest the article in the 

 February number on the respiration of 

 fishes, and believe others did likewise. 

 Carrying the idea a step further the 

 following experiment to demonstrate 

 osmosis may appeal because of its sim- 

 plicity and ease of operation. It shows 

 one of the fundamental facts of life in 

 an accurate and scientific manner. 



In order to understand just how the 

 oxygen passes in and the waste gases 

 out through the delicate gill membrane 

 of fishes it is necessary to go to a scien- 

 tific laboratory for a satisfactory expla- 

 nation. Under the most powerful mi- 

 croscope yet devised no pores in the 

 membranes are discernible. It is a 

 question to which no real answer has 

 yet been given as to just how the gases 

 penetrate the membrane. However, it 

 is known that this does take place. 



and scientists have named the process 

 osmosis. 



It can be shown by experiment that 

 if two gases, or liquids, be separated 

 by an animal membrane a transfer of 

 the two will take place through the 

 membrane. It will be found that the 

 transfusion takes place in both direc- 

 tions but the greater flow will be in the 

 direction of the denser of the two. The 

 experiment with the gases is difficult 

 to work outside of a laboratory, but 

 anyone in the quiet of their own 

 kitchen, if the "Madam" is out, may 

 demonstrate this phenomenon with 

 liquids. 



A tube is required, an old test tube 

 with the bottom broken off will do. 

 Over the smooth end of it the thin skin 

 found next to the inside of an egg shell 

 must be stretched and sealed around 



