Venning was in time next day to receive his instructions, and made in his note-book an outline sketch of each part.  While he was so engaged, Mr. Hume, with Compton, were seeing the outfit packed for the steamer, every purchase having been made with great judgment, so that nothing superfluous figured in the list.  Their armament consisted of one double express for Mr. Hume, two sporting carbines for the boys, three Mauser revolvers, and one fowling-piece, strong hunting-knives, as well as four Ghoorka knives for cutting a path through the forest.  As far as possible all their food-stuff was concentrated in tabloids and essences; each had his own special tin-lined medicine-case, in addition to the common drug-chest; each his own water-bottle of double canvas, a material which, permitting evaporation, keeps the water cool; and each his regulation “billy,” or cooking-tin.  As for clothing, it was a mixture of luxury and rough wear, of the best silk underwear, cellular shirts of a light blue, and yellow chamois-skin breeches, warranted to grow tougher with use.  Putties were discarded, as likely to give harbourage to “jiggers,” which bore into the toes, in favour of soft leather high boots, tightly fastened at the knee; and the outfit included needles for the making of moccasins, or veld schoen, from the hides of the larger antelope.

“Why do you select all blue shirts, Mr. Hume?” asked Venning.

“On account of the mosquitoes.”

“Consider the feeling of the gorillas,” said Compton, dryly.  “Perhaps they would prefer green.”

“They may find us green enough for their taste, Compton; but I am not joking.  Mosquitoes have a preference for some colours and an aversion for others.  They dislike blue most of all, so you see I have a purpose in selecting blue—­not only for the shirts, but for the mosquito curtains.”

“All these precautions for a wretched fly.”

“Exactly.  A mosquito’s gimlet carries more terrors for the explorer than the elephant’s trunk, and his hum is more dreaded than the roar of the lion.  The mosquito is fever-winged, alert, and bloodthirsty.  He carries the germs of malaria with him; and malaria kills off more men than all the reptiles and wild animals combined.”

“Is there no way of fighting?” asked Compton, impressed.

“Oh ay; they are fighting him on the West Coast by draining the swamps, where he breeds about the villages.  But who can drain the swamps of the Congo, or let light into the Great Forest?”

“Then we stand a fair chance to catch malaria?”

“A better chance,” said Mr. Hume, grimly, “than we have of catching the okapi.  Fear the mosquito, but at the same time take every precaution against its attack.  I have an idea myself that nature has provided a safeguard.”

“Quinine?” said Venning.