Why does Diana call the threading of the bobbin "The kiss of death" in Katherine Paterson's Lyddie?

The
episode with the bobbin highlights one of the book's major themes: the appalling working
conditions common in 19th century America. Asdiscovers during her time at the factory, worker
safety isn't exactly the management's top priority. Accidents are common, but without any
employee compensation or an alternative source of income, the girls at the factory have no
choice but to toil away in unsafe conditions.

At the same time, there are
many dangers inherent in factory work about which the management, and everyone else, are
genuinely ignorant. One such danger is the so-called "kiss of death." As part of their
work, the girls are required to breathe on threads to pull them through the "hole" or
eye of the shuttle. This has the effect of spreading highly contagious diseases such as
tuberculosis, which at that time was virtually incurable, especially in its advanced
stages.