326 



SCIENCE, 



[Vol. XIII. No. 325 



dured by us from June 28 to Dec. 5, 1887, and from June i, 1888, 

 to the present date, to continue again from the present date till 

 about Dec. 10, 1888, when 1 hope then to say a last farewell to the 

 Kongo forest." 



Mr. Stanley's description of the daily course of things in the 

 forest region is worth quoting : " The mornings generally were stern 

 and sombre, the sky covered with lowering and heavy clouds ; at 

 other times thick mist buried every thing, clearing off about 9 A.M., 

 sometimes not till 11 a.m. Nothing stirs then: insect-life is still 

 asleep ; the forest is still as death ; the dark river, darkened by 

 lofty walls of thick forest and vegetation, is silent as a grave ; our 

 heart-throbs seem almost clamorous, and our inmost thoughts 

 loud. If no rain follows this darkness, the sun appears from be- 

 hind the cloudy masses, the mist disappears, life wakens up before 

 its brilliancy. Butterflies scurry through the air, a solitary ibis 

 croaks an alarm, a diver flies across the stream, the forest is full of 

 a strange murmur, and somewhere up river booms the alarum 

 drum. The quick-sighted natives have seen us, voices vociferate 

 challenges, there is a flash of spears, and hostile passions are 

 aroused." 



Stanley does not give very detailed information regarding the 

 tribes met with, except the statement that five different languages 

 are spoken. He says that Negambi Rapids, about two hundred 

 and fifty miles above the junction of the Avuvimi and the Kongo 

 marks the division between two different kinds of architecture and 

 language. Below, the cone-huts are to be found ; above the rapids 

 we have villages, long and straight, of detached square huts sur- 

 rounded by tall logs, which form separate courts, and add mate- 

 rially to the strength of the village. Many precautions had to be 

 adopted against attacks by poisoned arrows. Mr. Stanley lost 

 several men by these arrows, and Lieut. Stairs had a narrow escape. 

 It was afterwards found that the poison is manufactured from the 

 dried bodies of red ants or pismires ground into powder, cooked in 

 palm-oil, and smeared over the wooden points of the arrows. As 

 might have been expected, the forest is haunted by myriads of in- 

 sects of every variety. 



THE INFLUENCE OF CERTAIN DRUGS ON PHYSICAL 

 STRENGTH AND ENDURANCE. 



T. Frederick PearSE, M.D., in an article in Knowledge, says 

 that certain drugs have a great reputation for increasing physical 

 endurance. These are chiefly coca, caffeine, and kola-nut ; and 

 there are certain other chemical compounds of analogous composi- 

 tion which are derived from muscular tissue, and have been found 

 experimentally to have a similar effect. These are chiefly creatine 

 and hypoxanthine. The chemical relation of all these substances 

 is very interesting. Strange to say, some are themselves the prod- 

 ucts of muscular waste. It will be noticed, also, that creatine 

 and hypoxanthine occur in beef-tea, which is so well known as a 

 general restorative and as a nervous stimulant, and there is ample 

 experimental proof that it assists muscular power. The chemical 

 relationship of the alkaloids found in tea, coffee, kola, and coca to 

 the products of muscle-tissue metamorphosis suggests that these 

 products are either replaced in the muscular tissue by these drugs, 

 or that the products act on the nervous system either as a food or 

 as a stimulant, and are merely supplemented in their action by the 

 drugs. It is a very interesting question whether these alkaloids 

 act locally on the muscle substance or upon the central nervous 

 system. 



As we know that tea, coffee, cocoa, and beef-tea sustain and 

 strengthen the nervous energies when they have been exhausted by 

 ■other than prolonged muscular action, the inference is that these 

 substances, as well as the analogous products of muscular tissue, 

 act also directly as food or stimulant to the nervous centres. Dr. 

 Pearse has tested and found by experiment the powers of caffeine in 

 increasing the respirations, and in strengthening as well as increas- 

 ing the rapidity of the heart's action. 



The following statements have been made by different writers 

 as to the value of these substances. Of coca, Markham's Pei'u- 

 vian Bark says it enables a greater amount of fatigue to be borne 

 with less nourishment, and it lessens the difficulty of respiration in 

 ascending mountain-sides. The Practitioner says, "The leaves 



are chewed to appease hunger and support strength in the ab- 

 sence of food, and used generally for the stimulant and narcotic 

 effects of tobacco and alcohol ; " the Lancet, " It is of use to steady 

 nerves of excitable persons (to a sportsman in shooting, for ex- 

 ample), to give endurance ; it is used by travellers in Bolivia and 

 Peru to counteract the effect of rarefied air on mountains." Lauder 

 Brunton writes, " In small doses it is said to lessen fatigue and 

 enable the Indians in Peru to make long marches, and a similar 

 result has been obtained in trials upon soldiers in Germany." Ex- 

 perimentally, coca appears to act in small doses as a stimulant to 

 the nervous system, affecting first of all the cerebral hemispheres, 

 next the medulla, and lastly the spinal cord. It lessens the feeling 

 of fatigue, but the only mental effect seems to be an exhilaration of 

 spirits. Like caffeine, it increases the rapidity of the heart-beat, 

 and raises the blood-pressure. 



Experimentally, caffeine has been found, in small doses, to 

 quicken the respiration and also the pulse. It seems to affect the 

 accelerating centre directly, as its action is equally well defined 

 after the nerves have been divided. Besides increasing the rapidity 

 of the heart's action, it seems also to strengthen it, and it raises 

 the blood-pressure. Caffeine also seems to lessen tissue change 

 and waste. In addition, caffeine appears to have some power 

 in paralyzing the conducting power of the sensory parts of the 

 spinal cord, and it may be in this way that it relieves the sense of 

 fatigue. At the same time, however, it is found to increase gen- 

 erally the functional activity of the spinal cord. H. C. Wood says, 

 " The peculiar wakefulness, the increased mental activity, and the 

 often nervous restlessness which are induced by strong coffee are 

 familiar to almost every one. By doses of two or three grains of 

 caffeine, a very similar state of the body is induced. The increase 

 of brain-power which has been noticed by various observers after 

 caffeine, as well as after coffee, tea, guarana, and all the allied 

 crude drugs, is undoubtedly real, and must be due to a direct 

 stimulant action on the cerebrum. It appears to me that the cere- 

 bral stimulation of caffeine differs from that of opium, in that it 

 affects the reasoning faculties at least as profoundly as it does the 

 imagination. Coffee prepares for active work both mental and 

 physical ; opium, rather for the reveries and dreams of the poets. 

 The enormous use made by mankind of substances containing 

 caffeine indicates that in some way it is directly of service in the 

 wear and tear of life." 



The nuts from the kola-tree {Stercttlia acuminata), a native of 

 tropical Africa, are used to support the strength, allay the appe- 

 tite, assuage thirst, and assist the digestion. They have also a 

 reputation for increasing the capacity to bear prolonged fatigue. 

 The kola-nuts contain a large percentage of the same chemical 

 principle, theine, as is contained in tea and coffee. They also con- 

 tain an aromatic volatile oil, to which some of their properties must 

 be attributed. The seeds have been employed as a remedy for 

 drunkenness, and they are said to abate the drink-crave. By vir- 

 tue of the alkaloids, caffeine and theobromine, contained in kola, it 

 must act as a cardiac tonic, improving both the force and rhythm 

 of the heart. The kola-nut is slightly bitter and astringent, and its 

 reputed value in digestive disturbances and diarrhoea may be based 

 on these properties. 



Of all inorganic compounds, the phosphates seem perhaps of the 

 greatest importance in animal tissues. They are found in consid- 

 erable quantity in the human body wherever active cell-growth is 

 going on. They must be ranked among the most valuable and 

 necessary foods. Their acknowledged value in disorders of the 

 nutritive system of children, and also in convalescence from acute 

 as well as wasting diseases, in all of which rapid growth and tissue 

 development is taking place, is good ground for the practical in- 

 ference that they are intimately concerned in nutrition generally, and 

 especially in the recuperation of parts worn out by disease. The 

 recovery from prolonged and severe exertion also may very probably 

 be assisted by them. The compounds of the meta-, pyro-, and 

 hypo-phosphates, in which the element phosphorus is loosely com- 

 bined, seem much more efficacious than the ordinary salt. According 

 to Ashburton Thompson, repeated doses of phosphates improve the 

 appetite, increase the rate of the circulation, sharpen the mental 

 faculties, increase the muscular power, and give a sensation of 

 well-being. 



