Subject: What is the toxicity levelof toxic called 'persin' in the avocado fruit?

We are the best researchers of our school. But we can't find the exact toxicity 
level of said toxic called persin found in avocado fruit. We are tying to 
gather facts and informations about the said toxic. Why does it doesn't harm 
humans? Why it does harm common pets, like birds and etc.? How can we find ways 
to uncover the truth? Could you advise me of what are we going to do?

Re: What is the toxicity levelof toxic called 'persin' in the avocado fruit?