2 Metabolism of Healthy Max. 



medicine, but there is a strong feeling that the nutritive processes during dis- 

 ease have been too little studied, in spite of the admirable researches of von 

 Noorden, Magnus-Levy, Naunyn, and others. A decided advance has indeed 

 been made in the general knowledge of physiology and excellent results have 

 been obtained in the field of pathological research, and yet the data regarding 

 pathological metabolism are too often of little or no value owing to the fact 

 that there is still a lack of adequate comparative data during health. 



Limitations of Normal Data and Accepted Standards. 



An intelligent study of pathological metabolism can only be made after a 

 thorough investigation of normal metabolism. In dealing with sickness, there 

 is a constant desire on the part of the physician for knowledge regarding the 

 patient's normal physiological processes. If he knows exactly what is the 

 course of events in a normal life, he can much more satisfactorily interpret 

 the abnormal course that life may take during disease. This is true not only 

 for the complex chemical and energy transformations, but for the simpler 

 indices of life processes, such as the rate of the heart-beat, respiration-rate, and 

 body- temperature. 



The accumulations of years of observation on these fundamental indices by 

 innumerable physiologists, medical examiners, and military physicians have 

 given us certain average values that are called normal, and yet a critical ex- 

 amination of the methods used by the various writers, and of the condition, 

 both physical and psychical, of the subject at the time of the examination, 

 gives us an undeniable right to question the values thus obtained as normal 

 values. 



Normal body-temperature. With body-temperature, the averaging of a great 

 number of measurements has resulted in the common belief that 98.6 F. is 

 the normal body-temperature. This assumption may lead at times to consid- 

 erable difficulty by virtue of the fact that many people otherwise perfectly 

 healthy may have a subnormal or hypernormal temperature. Furthermore, 

 we now know that the normal body-temperature varies perceptibly with mus- 

 cular work and even with the time of day. Similarly, the respiration-rate, 

 pulse-rate, and blood-pressure all range within certain limits, the average of 

 which is called normal. 



Change in tody- weight as index of physical condition. In addition to the 

 pulse, temperature, and respiration, the physician is constantly inquiring into 

 the variations in body-weight. Our knowledge of the changes in body-weight 

 and the factors upon which they depend are notoriously unsatisfactory and 

 uncertain. The income of the body is made up of a large number of elements 

 water, protein, fats, carbohydrates, ash, and oxygen from the air. The outgo 

 consists of water of urine and feces, water-vapor, carbon dioxide, and the Tin- 

 oxidized material in feces and urine. In attempting to strike a balance between 

 income and outgo one may find very wide discrepancies between the apparent 



