328 



NA TURE 



[Feb. 26, 1874 



cavity has its analogue in that of the bellows {d). The 

 elastic reservoir, together with the tubes, corresponds to 

 the systemic arteries, the gas-bag connected with the 

 tube f (the capillaries) to the systemic veins ; and the 

 tube g to the coronary arteries, which supply the muscu- 

 lar tissue of the heart with nutrient blood, just as it does 

 the boiler by means of the burner h. This, however, 

 does not show that the pumping power of the heart varies 

 directly as the blood-pressui-e ; that such is the case de- 

 pends on the opportunity offered by the sphygmograph- 

 trace for the estimation of the length of the ventricular 

 systole under different circumstances. Each beat or revo- 

 tion of the heart is divided into two main parts — (l) the 

 period of contraction or s\ stole, and (2) the period of re- 

 pose or diastole. The former of these occupies the inter- 

 val between the commencement of the primary rise and 

 that of the dicrotic rise in the sphygmograph trace ; the 

 latter from the dicrotic rise to the commencement of the 

 succeeding primary rise. In all good tracings from 

 healthy pulses these two points, the primary and dicrotic 

 rises, are readily found ; and their relative lengths can be 

 estimated with great accuracy. A large number of mea- 

 surements have enabled me to prove that the 7-clativc 

 lengths of the systolic and diastolic portions of the pulse- 

 trace do not vary for any given pulse-rate. But, as will 

 be granted by most physiologists who have worked at the 

 subject, the blood-pressure in the arteries is quite indepen- 

 dent of the pulse-rate. Consequently the heart may be 

 doing very different amounts of work without any varia- 

 tion in the pulse-rate, which is the same thing as saying, 

 with the same length of systole ; which makes it evident 

 that, as in the above-described engine, the force of the 

 cardiac muscular contraction varies directly as the blood- 

 pressure, knowing what we do about the flow of fluids 

 through capillary tubes, and the capacity of the arterial 

 system under different degrees of blood-pressure. 



The sphygmograph trace tells us more than this. 

 Though the length of the systolic portion of the beat does 

 not change with any given pulse-rate, nevertheless it does 

 so greatly with different rapidities of pulse ; my obser- 

 vations showing that the length of the systole varies as 

 the cube root of the whole beat, being found from the 

 equation xy' = 47 ^ ^J x when x = the pulse-rate and 

 y' = the ratio borne by the systole to the whole beat. 

 From this no other inference can be drawn than that 

 the length of the diastole, or period of cardiac rest, 

 during which fresh blood is circulating through the ven- 

 tricular walls, must modify the contractile force of its 

 muscular substance. The e.xact extent of this influence 

 can be more readily estimated by a study of the cardio- 

 graph trace, which is obtained by applying the sphygmo- 

 graph to the side of the chest at any spot where the 

 pulsations of the heart are to be felt. It may, from the 

 thus obtained curves, be demonstrated that if not ex- 

 actly, approximately, at least, the nutrition of the heart's 

 walls must vary as the square-root of the length of the 

 diastolic period. * 



There is much, therefore, as I hope I have been able to 

 show, to be learned respecting the action of the heart 

 from measurement of sphygmograph tracings, and it is 

 scarcely too bold to extend the generalisation to the pro- 

 perties o( muscular tissue generally ; for the fact that 

 each beat depends entirely for its efficiency on the pecu- 

 liarities in the blood-pressure and the duration of the 

 previous diastole, removes all complications as to incom- 

 pleteness of exhaustion, and all doubts as to the exact 

 amount of work done by the muscular fibres themselves 

 of that most perfect of engines, whose extreme perfection 

 enables it to complete in most of us something like 

 750,000 beats in a week, and nearly thirty thousand mil- 

 lion revolutions in a person by the time he is seventy 

 years of age. 



* yournat of Anatomy and Physiology^ May and November, 1873. 



DR. VON MIKLUCHO MAC LAY'S RE- 

 .SEARCHES AMONG THE PAPUANS* 



^ITHEN lately at Buitenrovg — the scarcely euphonious 

 '* equivalent of the "Sans Souci" of a former 

 English Governor of Java — we had the good fortune 

 to make the acquaintance of the owner of a name, whose 

 peculiarity, no less than fame, has rendered it familiar to 

 every biologist. 



The friends — and we are sure they must be numerous — 

 of Dr. Miklucho Maclay will regret to hear that he is de- 

 termined, in spite of an aguish fever which still clings to 

 him, and of, it is feared, some serious implication of the 

 liver, to start again in a few days for the scene of his 

 recent labours — the east coast of New Guinea, where 

 he had previously spent fifteen months in close inter- 

 course with the natives. 



On September 19, 1871, the Russian corvette Vitias 

 cast anchor in Astrolabe Gulf, and Dr. Maclay landed 

 with two servants, one a Polynesian, the other a 

 Swede. After a hut of very modest dimensionsf had 

 been built for him by the ship's carpenter, the Vitias 

 weighed anchor on the 26th, and departed. 



Dr. Maclay was soon left practically alone, and depend- 

 ent entirely upon himself, for the Polynesian servant 

 died early in December of a chronic (ever which he had 

 when he started, and the .Swede soon followed suit, with 

 the exception, that he did not die, but by constant ailing 

 was a source of much encumbrance to his master. 



As the natives were very distrustful, scarcely answering 

 any questions, Dr. Maclay did not make much progress 

 with the essential task of learning the language. Not 

 only, however, were they suspicious, but determined to 

 discourage the presence of the stranger by shooting arrows 

 close to his head and neck, and pressing their spears so 

 hard against his teeth, that he was constrained to open 

 his mouth. Finding that he did not only not take 

 the least notice of these annoyances, but that all his ac- 

 tions toward them were good (for, he being a doctor, 

 his utility in the economy of the community was soon dis- 

 covered), they concluded that he was no ordinary mortal, 

 but that he was the veritable man-in-the-moon (" Karam- 

 tamo "), and paid him due respect accordingly. 



As there were footpaths only in the neighbourhood of 

 the villages, and as these latter were never found at a 

 greater elevation than 1,500 feet. Dr. Maclay had some 

 difficulty in making expeditions without guides, which at 

 first were difficult to procure. 



During his stay in New Guinea Dr. IMaclay studied the 

 inhabitants of the whole coast of Astrolabe Gulf; the 

 people of the mountains round the gulf, and the dwellers 

 on the islands near Cape Duperre, one of the boundaries 

 of the gulf, who lived a life of such perfect peace that he 

 called the islands '' the Archipelago of Contentment." X 

 The inhabitants, too, of Dampier Island (Kar-kar) paid him 

 visits. The inhabitants of " Maclay Coast," by which name 

 Dr. Maclay proposes to call the coast skirting the edge of 

 the Astrolabe Gulf, were of especial interest, as it seems 

 that they have never been in intercourse with any civilised 

 people, for not only were all their tools and weapons made 

 out of stone, wood, or bone, but no trace of any European 

 ardcle could be found among them. These people 

 treasured up, or exchanged as valuable, the smallest trifles 

 which were given them, e.g. fragments of broken bottles, 

 with which they shaved themselves, as a substitute for 

 flint, or the sharp edges of grasses. 



* " Anthropologische Bemerkungen ueber die Papuas der MacKiy Kiiste in 

 Neu Guine.i." Kepriiit from the Natiirkundtg Tijdscltri/t voor Neder- 

 lattdsclt Indif Dct-l xxxiii. Mijtl Verbiijf aan de Oostkiist van Nieuw 

 Guinea. Ilmi. (liatavia, 1873). 



t Only 7 feet broad, and 14 feet long, and divided by a screen of sailcloth 

 into two rooms, one for his servants, the other for himself- The hut w-is 

 situated on the south coast of Astrolabe Gulf, midway between the two 

 capes, its boundaries. 



t "Archipel der zufriedcnen Menschen." 



