her academic career began with research into the defence mechanisms of now extinct exocranial tribes entitled `` pithecanthropous : raising hackles among the giant heads '' , a success followed swiftly by a paper on methods of crop irrigation in primitive agriculturally based cultures entitled `` potatoes : raising yields among the spud heads '' , and a breakthrough book on the role of precious stones in defining the biological characteristics of the people occupying areas wherein such gems are unearthed , entitled `` pearls before swine : raising expectations among the rock heads '' .