Preparing a dilution series of the seed stock makes it more quantitative, but by far the easiest and fastest method for seed transfer is streak seeding. This method uses an animal whisker (usually cat or rabbit) as a seeding wand, which is touched or stroked over the surface of the parent crystal to dislodge and trap the nuclei. The whisker is then drawn through the new drop, depositing the seeds in a streak line. Although seeding wands have been made from thin glass rods, platinum-wire inoculation loops, and acupuncture needles, animal whiskers or hairs offer a definite advantage. The overlapping cuticles capture the seeds effectively. Here we would like to bring attention to an animal source of material for making seeding wands which, at least to our knowledge, has not been exploited much by the crystallization community. Horse tail hair is much more abundant than most animal whiskers, which makes it useful when organizing large scale laboratory sessions. In addition, horse tail hairs maintain the same thickness throughout their length (which is why violin bow makers use it), and this property may be useful in its own right for reproducibility in seed transfer. On the other hand, a cat whicker can be cut into three or four segments to obtain wands of different thickness. We use both horse tail hairs and cat whiskers because of their complementary properties. We find that rabbit whiskers, being thinner than both horse hair and cat whiskers, are too flexible.
--Therese Bergfors. Seeds to crystals. Journal of Structural Biology, 2003.
