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ACellulomonas spp isolated from soil produced carboxymethyl cellulase (CMCase) and xylanase enzymes. Cobalt (0.1mm) and nickel (0.1mm) decreased the growth rate ofCellulomonas spp. These metal ions activated CMCase activity but not xylanase activity; cobalt being the greater stimulatory ion than nickel. A predominant long lag phase was observed in adapted cells when compared with the non-adapted cells. However, the growth level of control cells was never obtained by the adapted cells.

The circulatory system in insects is almost entirely of the open type wherein the haemolymph is confined to the body cavity or haemocoel. The dorsal vessel is a closed structure and considered to be the ‘primary circulatory pump’ (Jones, 1964) or the ‘dorsal pulsatile organ’ (Jones, 1977). The dorsal vessel, various accessory pulsatile organs and septa help to direct the flow of the haemolymph as well as the body movements of the insect. The haemolymph is the extracellular circulating fluid that fills the body cavity of the insect. It is physically isolated from direct contact with the body tissues by a thin permeable membrane which lines the haemocoel. The haemolymph contains organic and inorganic components in addition to cellular elements termed haemocytes.

A single ventral oesophageal diverticulum is present in adult Papilio aristolochiae (Lepidoptera: Papilionidae), and a histologic development of this has been studied in detail. The larval oesophageal valve from which the ventral diverticulum arises, has been divided into 5 different regions. The fate of all these regions has been followed during pupation. Cells of the anterior imaginal ring in the pupa divide mitotically and furnish the cells of ventral evagination, which forms the ventral diverticulum. The ventral evagination grows as a result of increase in the number of cells and also cell enlargement. Regions 4 and 5 degenerate completely in the adult, and the degenerated cells are thrown into the body cavity.

When the salivary glands of 10-day-old adult Periplaneta americana L. are removed, a gradual decline in midgut invertase activity is found. No such effect occurs in cockroaches whose salivary ducts are severed. An injection of salivary gland extract in the haemocoel of salivarectomized insects causes the reestablishment, to a large extent, of the normal midgut enzyme levels. The possibility of the involvement of a non-exocrine factor from the salivary glands is discussed.

Quantitative changes in the total protein in the brain of aging male and female Periplaneta americana have been observed. A significant increase of total protein and neurosecretory cells in the brain up to 5 months, followed by a considerable decline in later age, points to a direct relationship between the neurosecretory cell number and reproductive phenomenon. Higher total protein concentration and cell number maintain reproduction up to 5 months while a decline after 6 months of adult life adversely affects reproduction. This suggests that neurosecretory cell number and protein concentration are related to reproduction and thereby aging.

It was experimentally demonstrated, by the surgical removal of salivary glands and severence of salivary ducts, that most of the amylase in the gut ofPeriplaneta americana comes from the salivary glands.