Louse eggs contain a single embryo. The adult female louse secretes glue that quickly hardens into a sheath that covers the hair shaft and the entire egg. This glue is very strong and that is what makes it very difficult to comb out the nits. Many lice home remedies may have a high kill rate but you still have to comb out all the nits. To accomplish that you need a good lice comb. The metal combs are better then the plastic lice combs because the teeth stay close together and give you a better chance of catching all the nits.