viNAL COMMON MISTAKES IN NATURAL HISTORY 339 



5. Mosquitoes bite — It is rather a difficult thing to prove to 

 some people that the mosquito does not bite. One man wrote 

 "I know it." 73 wrote the fact of the case that they pierce and 

 do not bite. It is also interesting to note that only "she bites," 

 "he is a gentleman." 



6. Little flies grow into large flies — ^An adult fly, when it comes 

 from the pupal case is as large as it will ever be. Few people 

 know that the fly does its growing when in the maggot stage. 

 37 of the people examined knew about the growth of flies. 



7. Man and animals eat food — "Man and animals" is a com- 

 mon mistake. It should be "Man and other animals" for man is 

 an animal. A total of 20 noticed the error. 12% of the men in 

 proportion to 6% of the women of college freshmen recognized this. 



8. Oxygen purifles the blood — The red corpuscles of the blood 

 simply act as vehicles of transportation. They carry the oxygen 

 from the lungs to the cells. Only five indicated that oxygen does 

 not purify the blood. The purest blood in the body is the blue 

 venous-blood as it leaves the kidneys. 



9. Oxygen builds up the body — Oxygen tears down the tissues 

 and thereby we obtain energy to do work. This knowledge was 

 limited to twenty. 



10. Plants breathe — Many believe that animals take in oxygen 

 and give off CO2 and that plants take in CO2 and give off oxygen. 

 Both respire and in the same way. Plants have the additional 

 power of taking in CO2, assimilating the carbon and giving off 

 oxygen. Plants do not breathe. They do not have a respiratory 

 movement. 



About What is the Size of the Largest Animal Cells? 



The majority of students believe that cells are always microscopic. 

 Birds eggs are cells. The ostrich egg is the largest living cell. 

 Nerve cells are often 2}4 feet in length. 



Where do Dragons Exist? 

 The answers may be tabulated as follows: 



