Other extracts from periwinkle help lower blood sugar in diabetics and are the basis for powerful tranquilizers.
Specific botanical types include poppies, sunflowers, daisies, violets, carnations, periwinkle and lily-of the-valley.
It was also confirmed that periwinkles were not affected.
The periwinkle effects found for longevity of cercariae released by periwinkles from polluted sites are also consistent with varying tolerance, although they could reflect differing metal accumulation.
It remains an open question whether young children can benefit from a more implicit form of contrast (as in the ' periwinkle ' example above).
For each test seawater solution 10 replicate trials using cercariae from each of 3 periwinkles were carried out.
Using mounted needles the reproductive tissue and digestive gland were teased apart to ascertain the presence/absence of periwinkle brood or trematode presence.
This protocol was repeated 10 times for each batch of cercariae from each periwinkle, taking less than 30 min per batch.
