have an exception."

"I should think the biggest difference would be that animals eat plants
and plants eat--what do plants eat?" ended Dorothy lamely.

"That is the biggest difference," assented Helen. "Plants are fed by
water and mineral substances that come from the soil directly, while
animals get the mineral stuff by way of the plants."

"Father told us once about some plants that caught insects. They eat
animals."

"And there are animals that eat both vegetables and animals, you and I,
for instance. So you can't draw any sharp lines."

"When a plant gets out of the cell stage and has a 'root, stem and
leaves' then you know it's a plant if you don't before," insisted
Dorothy, determined to make her knowledge useful.

"Did any of you notice the bean I've been sprouting in my room?" asked
Helen.

"I'll get it, I'll get it!" shouted Dicky.

"Trust Dicky not to let anything escape his notice!" laughed his big
sister.

Dicky returned in a minute or two carrying very carefully a shallow
earthenware dish from which some thick yellow-green tips were sprouting.