January 25, 1912] 



NATURE 



435 



following is a short preliminary account of a series of 

 observations made in the summer of 19 ii on the summit 

 of Pike's Peak, Colorado. Pike's Peak is 14,107 feet 

 above sea-level, the barometric pressure on the summit 

 being about 18 inches (457 mm.). There is an excellent 

 stone house close to the summit, in which the authors 

 were accommodated during their stay of five weeks. The 

 main object of the expedition was to discover to what 

 extent, and by what means, adaptation takes place to low 

 barometric pressure, and consequent deficiency' in the 

 partial pressure of oxygen in the air. The authors' chief 

 conclusions are as follows : — (i) After two or three days 

 on the summit of Pike's Peak very distinct signs of 

 acclimatisation began to appear. (2) Before acclimatisa- 

 tion occurred, blueness of the lips and face, nausea, in- 

 testinal disturbance, headache, fainting in some persons, 

 and periodic breathing were observed, besides great 

 hyperpnoea on exertion or holding the breath for a few 

 seconds. (3) All these symptoms are referable, directly or 

 indirectly, to want of oxygen produced by the diminished 

 partial pressure of oxygen in the air. The authors did not 

 observe, either in themselves or in the large number of 

 persons who ascended the peak, any symptoms (apart from 

 the effects of the bright light) not referable to the same 

 cause. (4) After acclimatisation had occurred these 

 symptoms disappeared, with the exception that hyperpnoea 

 on exertion or on holding the breath for a few seconds was 

 still much greater than usual. Periodic breathing was still 

 observed occasionally, and blueness of the lips and face 

 was present after continuous and powerful exertion, such 

 as walking up hill. (5) The respiratory exchange during 

 rest remained about normal in the one subject on whom 

 exact experiments were made, and the respiratory exchange 

 during work did not appear to be markedly increased. 

 (6) After acclimatisation the alveolar carbon dioxide 

 pressure was diminished from about 40 mm. to about 

 27 mm. during rest or moderate exertion, which corre- 

 sponded to an increase of about 50 per cent, in the ventila- 

 tion of the lung alveoli. During severe exertion the 

 alveolar carbon dioxide pressure was about half what it 

 normally is during similar exertion, which corresponded to 

 an increase of about 100 per cent, in the hyperpnoea ; and 

 owing to a temporary alteration in the respiratory quotient 

 the breathing was still further increased, so that it was 

 for a time increased to thrice what it would have been at 

 sea-level with the same oxygen consumption. (7) The 

 change in the level of alveolar carbon dioxide pressure 

 occurred gradually after going up, and disappeared gradu- 

 ally on coming down, the change taking a number of days 

 I to reach completion. (8) The percentage of hajmoglobin 

 j in the blood increased for several weeks on the summit of 

 Pike's Peak, and varied in different acclimatised persons 

 from 115 to 154 per cent, on the scale of the Gowers- 

 Haldane ha^moglobinometer, corresponding to an oxygen 

 capacity of from 21 to 28-5 c.c. of oxygen per 100 c.c. of 

 blood. The number of red corpuscles per cubic mm. of 

 blood increased parallel with the haemoglobin, and the 

 percentage volume of red corpuscles, as determined by the 

 haematocrit, also increased in proportion to the percentage 

 of haemoglobin. (9) A large increase in the total amount 

 of haemoglobin (determined by the carbon monoxide 

 method) in the body occurred during the first three weeks, 

 and along with this increase there was found, except in 

 the first week, a slight increase in blood volume, as well 

 as the increase, already referred to, in the percentage of 

 haemoglobin, (10) On coming down from Pike's Peak the 

 hemoglobin percentage diminished much more rapidly 

 ' than the total hiemoglobin, so that the blood volume was 

 still further increased at first. It required about four 

 weeks for the excess of haemoglobin and blood volume to 

 disappear, though the haemoglobin percentage fell to normal 

 much earlier. (11) So far as the authors could ascertain, 

 there was very little change in the rate of circulation on 

 Pike's Peak after acclimatisation. Pulse and blood 

 r -^sure were but little affected. In most cases, however, 

 "■ was a slight increase in the pulse-rate. (12) After 

 limatisation the oxygen pressure in the arterial blood 

 asured by the carbon monoxide method) rose during rest 

 ibout 35 mm. of mercury, or 66 per cent, above the 

 olar oxygen pressure, and remained at a level of only 

 ut 12 mm. below the normal oxygen pressure at sea- 

 i' vel. Immediately after ascending the peak, and before 

 NO. 2204, VOL. 88] 



acclimatisation had occurred, the arterial oxygen pressure 

 was found to be about 45 mm. below i^ormal, and only 

 slightly above the alveolar oxygen pressure. This change 

 appears to be due to a progressive increase in the activity 

 of the alveolar epithelium in secreting oxygen inwards. 

 On raising the alveolar oxygen pressure to normal, the 

 difference between alveolar and arterial oxygen pressure 

 diminished rapidly. (13) Acclimatisation to high altitudes 

 is due mainly to the increased secretory activity of the 

 alveolar epithelium, but partly also to the increased lung 

 ventilation, and to a lesser extent to the increased haemo- 

 globin percentage in the blood. The acclimatisation takes 

 some days to develop. During rapid ascents in balloons 

 or aeroplanes it would not have time to develop, and this 

 explains the contrast between the experience of balloonists, 

 &c., and that of mountaineers who ascend gradually. — 

 J. Barcroft : The effect of altitude upon the dissociation 

 curve of the blood. The affinity of haemoglobin for oxygen 

 depends, among other things, upon the hydrogen ion con- 

 centration of the blood. After removing the COj from 

 blood, a scale was made out for the blood of each person 

 plotting the percentage of oxyhaemoglobin at a standard 

 oxygen pressure vertically, and the amount of acid added 

 to the blood horizontally. Thus, by estimating the per- 

 centage of oxygen in the haemoglobin of blood at high 

 altitudes, an estimate can be made of the acid which has 

 been contributed to it by the organism. It thus appeared 

 that at each altitude the alkalinity of the blood decreased 

 (apart from COj). This was so in the resting individual, 

 but much more markedly so during exercise. The dis- 

 sociation curve of blood exposed to the COj pressure of the 

 alveolar air confirmed the result that during rest the 

 dissociation curve remains constant. During activity the 

 affinity of the blood for oxygen decreases, and the haemo- 

 globin is able to unite with less oxygen in the lung, and 

 to do so at a lower rate. On the other hand, the rate of 

 dissociation in the tissues increases. The acid which 

 accumulates in the blood is not lactic acid entirely, and 

 during rest only to a slight extent. The persons whose 

 blood was most alkaline (apart from COj) were most prone 

 to sickness. — R. Kirkpatrick : Note on Astrosclera 

 willcyana. Lister. Astrosclera willeyana, Lister, is a 

 small columnar, or mushroom-shaped, organism, somewhat 

 resembling a coral in appearance. It has been described 

 by various zoologists respeetively as a calcareous sponge, 

 a siliceous sponge, and a coral. Mr. Kirkpatrick, who 

 dredged numerous specimens from a depth of 50 to 100 

 fathoms off Christmas Island, Indian Ocean, has found 

 that the organism is a siliceous sponge with a supple- 

 mentary skeleton of aragonite, and that it owes its unique 

 character (viz. that of forming a supplementary skeleton 

 of aragonite) to its association with a degenerate Floridean 

 alga (red seaweed). Certain of the sponge cells envelop 

 the spores of the alga, and secrete around them concentric 

 layers of aragonite. The little spherules so formed are 

 in several respects comparable with the cyst pearls of 

 pearl oysters and mussels. The spherules are at first loose 

 and separate, but later become welded together so as to 

 form a firm coral-like skeleton. The encysted algal spores 

 may be killed and wholly calcified, or they may retain their 

 vitality and germinate, so as to form branching thread- 

 like filaments, which bore their way through the solid 

 calcareous walls. The algal plants in the soft tissues of 

 the sponge are of microscopic dimensions. — Dr. H. B. 

 Fantham : Hcrpetomonas pedicuU, nov. spec, parasitic 

 in the alimentary tract of Pediculus vestimenti, the human 

 body-louse. Herpetomonas pediculi is a parasitic flagel- 

 late protozoon. It has been investigated especially in 

 body-lice reared and fed on the author's own blood. It 

 also occurs in " wild " lice, but only some 8 per cent, are 

 infected, and then slightly. The life-cycle of the parasite 

 comprises pre-flagellate, flagellate, and post-flagellate 

 stages, which gradually merge into each other. These 

 forms of the parasite occur broadly in the fore-, mid-, 

 and hind-gut respectively of adult lice, while pre-flagellate 

 stages also occur in the digestive tract of larval pediculi. 

 The pre-flagellate stage resembles the Leishman-Donovan 

 body. The length of the flagellate body varies from 11 n 

 to 26 n, while the single free flagellum is usually about 

 as long as the body. Oval, encysted post-flagellate stages 

 may be recovered from the ifaeces of infected lice. Striated 

 thick-walled cysts occur very rarely. The mode of infec- 



