REVIEWS 32s 



The cold at high latitudes is more uniform, there being very little sun in 

 winter; and even in summer, although the sun shines nearly all the time, it 

 has not great heating power. At high altitudes the heating power of the sun 

 is great so that any object exposed to its rays is rapidly heated ; there being 

 thus marked variation in temperature between the shade and objects exposed 

 to the rays of the sun. 



Low temperatures kill or paralyse the activities of micro-organisms ; there- 

 fore food remains without putrefaction, and the danger of infection by patho- 

 genic organisms is decreased. 



The amount of water that can be present in the form of vapour is decreased 

 by low temperatures ; therefore a low absolute humidity is one of the char- 

 acteristic features at low temperatures. 



Clouds are infrequent because the moisture in the warmer air is condensed 

 at lower altitudes ; therefore in addition to greater heating power, the sun 

 shines for longer periods than at low altitudes. The result is that at high 

 altitudes one experiences cold nights with low absolute humidity, and warm, 

 sunny days. 



The decrease in atmospheric pressure means a proportional decrease 

 in the pressure of oxygen : this decrease in oxygen pressure is the limiting 

 factor to human life at high altitudes. Communities do not naturally Uve 

 near the limit imposed by lack of oxygen because of the difficulty in obtaining 

 a supply of food. 



There is a difference between going to a high altitude slowly, as in ascending 

 a range of mountains, and in ascending quickly, as in going up in a balloon. 

 In the former case changes take place in the blood producing acclimatisation, 

 whilst in the latter the blood changes consist in an incerase in the number 

 of red blood-corpuscles without a corresponding increase in the amount of 

 haemoglobin. 



Life at moderately high altitudes is not injurious to health, as shown in 

 vital statistics of monks at the Great St. Bernard Pass and of the inhabitants 

 at Canton des Orisons. 



The healthiness at high altitudes depends on the coldness, dryness, and 

 stimulant effect of radiant heat. 



In places one feels that the book would be improved by condensation. 

 There are one or two erroneous statements, such as on p. 67 : " dark pigmen- 

 tation of the skin ... is a preventive against radiation of blood-heat into 

 circumambient air." Physically dark surfaces radiate more than light ones. 

 Again, on pp. 96 and 99, there are some statements about carbon dioxide 

 which are not understandable. In spite of these defects, the book contains 

 much that is worth reading. 



H. E. R. 



The Principles of Ante-natal and Post-natal Child Physiology Pure and 

 Applied. By W. M. Feldman, M.B., B.S. [Pp. xxvii + 694.] 

 (London : Longmans, Green & Co., 1920. Price 30s. net.) 

 The development of a new individual involves a number of special adapta- 

 tions which are not found in the non-developmental period of adult life. The 

 physiology of these adaptations requires special treatment. No course of 

 physiology is complete without an outline of the period of development, 

 but the special problems of infant life cannot be treated fully in an elementary 

 course. The importance of this subject is especially great for the medical 

 practitioner whose practice is often largely concerned with children and their 

 development. 



The arrangement of the material in this book is chronological. Starting 

 with the preconceptional study of germinal cells, they are traced through 

 fertiUsation, growth, and development until puberty, when the individual 

 becomes an adult. 



