A balance of total water in the smoking of a cigarette is presented indicating theoretically calculated as well as experimentally determined quantities. Both groups of values are found to coincide to a large extent. As the quantity of the water of combustion of a given tobacco variety or tobacco mixture does not vary (Virginia: 314 mg per g of tobacco), changes of total water values are a function of the initial moisture content of tobacco only. Approximately 3 % of the total water leave the cigarette at its tip. Nearly 2 % penetrate the paper wrapping (without its burning ring), and 95 % escape from the incandescent end. The particulate phases of the studied smoke streams are poor in water, i. e. they include only 2 % of the total water, while the water content of the gaseous phases amounts to 98 %. The total water of a cigarette is found to be distributed among the particulate and gaseous phases of the various smoke streams as follows: mainstream smoke 3 %, glow stream 80.5 %, sidestream smoke 14.5 %, diffusion stream 2 % (maximum).
The average daily metabolic rate (ADMR) was determined for Peromyscus maniculatus by an open circuit oxygen consumption method and a field method based on food consumption. The ADMR determined by the field method, 0.015 kcal/gm/hr, was not significantly different from that derived from the oxygen consumption method, 0.016 kcal/gm/hr. These results suggest that either method might reliably be used to estimate the ADHR. The actual method employed should be determined by the equipment and finances available and the environmental conditions under which animals must be tested. One important aspect in the ecology of any area is the passage of energy between and within trophic levels. Various methods, and their limitations, to estimate the amount of this energy have been discussed elsewhere (Davis and Golley, 1961; Golley, 1967: Falls, 1968). The most commonly used laboratory methods for determination of metabolic rates are the oxygen consumption and food consumption methods (Morrison, 1948; Chew and Chew, 1970; Huberman and Fleharty, 1971; Fleharty and Choate, 1971; Kenagy, 1973). However, these methods have, in the past necessitated extrapolation to convert laboratory metabolic rates to the actual rates under field conditions (Colley, 1967). How these extrapolations should be performed has been the subject of controversy (Odum et al., 1962; McNab, 1963; Grodzinski and Gorecki, 1967; Chew and Chew, 1970; Fleharty and Choate, 1973). To overcome the problem of extrapolation, various methods have been developed to measure metabolic rates directly in the field. Radioactive and nonradioactive isotopes generally are used in these methods (Galley, 1967; Chew, 1971); comparison of the results of these field methods and those of traditional laboratory methods have shown close agreement (Mullen and Chew, 1973). The problem with the use of isotopes is that they are expensive and the standard deviation of the energy flow estimate may be quite large (Collins and Smith, 1974). To overcome this disadvantage, Collins and Smith (1974) developed a field method based on a relationship between the dry weight of food consumed and the dry weight of the stomach contents after a given interval of time. The purpose of this study was to statistically compare the average daily metabolic rate (ADMH) as determined by the field method of Collins and Smith (1974) with that estimated by means of a laboratory respirometer developed by Baar and Fleharty (1973).
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