Cum Grano Salis

Imagine you and the rest of your expedition are stranded on a distant planet. Food stores are running low, but the local trees produce a lovely chartreuse fruit. It's tasty and full of nutrients, but has the unfortunate side-effect of killing the experimental animals you've tested it on (as illustrated above). So what can you do?

"Cum Grano Salis" is a good old-fashioned science fiction problem story that was originally published in a 1959 issue of Astounding Science Fiction. Since figuring out the scientific solution to the problem is the whole point of the story, I won't give it away. But if you want a few hints, you can follow the links below (mousing over the links will probably give it all away):

• chartreuse is the same color as this pigment with this structure, which can have this property.
• Cum Grano Salis means this
  

Read "Cum Grano Salis" by David Gordon

(Edited to make the links clearer)
Illustration by Emsh (Ed Emshwiller) for "Cum Grano Salis", originally published in Astounding Science Fiction, May 1959, currently at Project Gutenberg. Colored by me.
Tags:science fiction, biochemistry