554 



NA TURE 



[April i 2, 1906 



poses through Mosso's endeavours. The first days 

 were most tempestuous, and the account of the stay 

 on the summit is full of interest; an incident in the 

 week was the recovery of a collapsed Alpine tourist, 

 who, to the surprise of the party, turned out to be a 

 lady. The whole party suffered more or less severelv 

 from mountain sickness, and a valuable part of the 

 investigations deals with this familiar complain!. 



Animals were taken up all the ascents for experi- 

 mental purpose^, others being left below for control 

 observations. 



The physiological results are related respectively to 

 the influence of moderate altitudes, i.e. up to 7500 feet, 

 and of high altitudes up to nearly 15,000 feet, the 

 former being chiefly the Brienz-Rothhorn experiments, 

 the latter the Monte Rosa ones. They may be briefly 

 summarised under the following different headings : — 



(1) Blo.nl Changes. — It is now well known that, as 

 first suggested by Paul Bert, the blood is altered in 

 high altitudes. The most striking change is that 

 discovered by Yiault, who found that the red blood 

 corpuscles increased from five millions to seven or 

 eight millions per cubic millimetre of blood. Similar 

 increase was observed in the present expedition, but it 

 was somewhat uncertain in character. The determin- 

 ation of the specific gravity of the blood and of the 

 serum showed that the increase when present was not 

 due to plasma diminution through the excessive 

 evaporation ol perspiration; moreover, an examination 

 in animals of the tissue which is the seat of the cor- 

 puscular formation (the red marrow of the bones) 

 showed that this was in a slate of greatly augmented 

 activity. There is therefore no question that the red 

 corpuscles increase in number, and the authors state 

 in their work that the stimulating influence is the 

 diminished oxygen tension of the blood itself. 



(2) Digestive Efficiency.- By careful quantitative ex- 

 aminations of the food and excreta, it was shown 

 that altitudes up to 8000 feel exercised a favourable 

 influence upon the completeness of the digestive pro- 

 cesses, the indigestible residues diminishing especially 

 when the surroundings were cold. In very hot sur- 

 roundings this favourable influence was not so ap- 

 parent, and in these circumstances muscular exer- 

 tion caused it to be of the reverse type. At very 

 high altitudes, 14,900 feet, the efficiency of digestion 

 was greatly impaired. 



(3) Oxidation Processes.- The extent ol these was 

 determined by the relation between the absorbed 

 oxygen and the total heat production of the bodv. It 

 appeared that even at such low altitudes as 1500 feet 

 the total oxidation was increased, this being excep- 

 tionally high during muscular exertion, whilst in 

 moderate and high altitudes the oxidation processes 

 were greatly increased. The increase is set down to 

 two circumstances; firstly, the diminished thermo- 

 genetic capacity of the muscles, which are impaired 

 by I he inadequate supply of oxygen in their circulating 

 blood, thus throwing the necessary heat production 

 upon the oxidation of more complex compounds than 

 those offered by the muscles ; secondly, the presence 

 in the tissues of abnormal oxidisable substances. 



NO. 1902, VOL. J $~\ 



(4) Protcid Metabolism. — The most important of 

 the numerous changes brought forward in the re- 

 sults of the expedition are those connected with the 

 fundamental nitrogenous substances, proteids. It 

 has been firmly established in physiology that whilst 

 every growing animal assimilates through food more 

 nitrogen than is excreted, this is not the case in the 

 adult except in special circumstances. Growth 

 implies proteid storage, which is believed to be utilised 

 for the increased formation of cellular structures, and 

 even in the adult such local muscular growth may 

 occur as the result of special muscular exercise, train- 

 ing, &c. , but it soon reaches a limit and is compara- 

 tively insignificant. In the convalescent it is a marked 

 feature of recovery from wasting illness. After mak- 

 ing due allowance for all disturbing influences, a most 

 important result was arrived at by the work of the 

 expedition. Even at Brienz (1500 feet) a stage was 

 reached in which the total N-import exceeded the 

 N-export, whilst on the Rothhorn this excess was most 

 marked. Moreover, this phase of metabolism persisted 

 for a considerable time after leaving the moderately 

 high altitude. This implies the production of a phase 

 of nitrogenous metabolism resembling that of the 

 growing animal; it is, in short, a renewal of youth. 

 It is noteworthy that along with this nitrogen storage 

 there was no corresponding increase of body weight, 

 the intensity of the oxidation processes in non-nitro- 

 genous compounds being more than sufficient to mask 

 the proteid gain. At the highest altitudes the gain 

 was not so apparent, but this is amply accounted for 

 by the digestive derangement which was associated 

 with the mountain sickness. 



(5) Respiration ami Circulation. — The decrease of 

 the oxygen tension in the blood in consequence of 

 the decreased partial pressure of the oxygen of the 

 air was in accordance with the results obtained by 

 Hiifner and others in connection with haemoglobin. In 

 opposition to Mosso's results the authors found that 

 there was not a decreased tension of carbonic acid 

 in the blood. They bring forward evidence which 

 suggests that deficiency of oxygen in the blood can, 

 like excess of carbonic acid, stimulate the respiratory 

 centre; this is of interest as it is opposed to the 

 physiological view now generally accepted. The 

 peculiar type of breathing known as the Cheyne- 

 Stokes respiration, described by Mosso as occurring 

 at high altitudes, was observed by the members of 

 the expedition on Monte Rosa, but the explanation 

 now advanced is quite different from that offered by 

 Mosso. Zuntz regards the phenomenon as impaired 

 activity of the respiratory centres, which are only 

 capable of being adequately roused if the carbonic 

 acid has by accumulation reached a certain tension 

 in the blood. 



As regards the circulatory changes, the only one 

 of a fundamental character appeared to be due to the 

 altered activity of the heart. At moderate altitudes 

 the heart's activity, like that of the respiratory 

 mechanism, is augmented to meet the need for more 

 oxygen and more effective oxygen transport by the 

 blood, but at very high altitudes there appeared to b 



