OXYGEN UXS ATI "RATION OF THE BLOOD 449 



longed oxygen deficiency, or it may be some toxic substance appearing 

 in the blood as a result, renders the hemoglobin less capable of carrying 

 oxygen by changing some of it into methemoglobin. It is at least sig- 

 nificant that this compound is formed in animals after massive injections 

 of streptococci (Peabody 7 *). The maintenance of an adequate tension 

 of oxygen in the plasma, by administration of oxygen by the lungs, 

 may retard the development of toxic substances. 



For similar reasons, the administration should be maintained until 

 all signs of deficient oxidation are removed, the best index of this being 

 the color of the face. So long as there is any anoxemia this is of a char- 

 acteristic pale ashen hue, different from that of ordinar}' capillary con 

 gestion. 



t Methods of Administration. It may be said at once that the common 



I clinical practice of placing a funnel connected with an oxygen tank 



|^in front of the patient's face is worse than useless. At the rate at which 



the oxygen is usually applied by this method, it is inconceivable how 



any measurable increase in the percentage of oxj^gen in the alveolar 



air could be attained, and if enough gas is turned on really to have some 



influence, the waste due to diffusion into the air is prohibitive. 



Where no special apparatus is obtainable for the administration, the 

 best -method is to pass a wide gum elastic catheter into one nostril, 

 through which the gas, after bubbling through water in a flask, is 

 passed as quickly as is comfortable for the patient. The method is ren- 

 dered much more efficient if the open nostril is closed by the attendant 

 during each inspiratory act. Dr. Rudolf and I have found by this lat- 

 ter method that the concentration of oxygen in the alveolar air can be 

 raised to 35 per cent, With the opposite nostril open, this percentage 

 was much less. 



When special appliances are available, a choice may be made between 

 a face mask, such as that devised for the purpose by J. S. Haldane, 70 and 

 which was extensively used in the treatment of gassed men, or an anes- 

 thetic mask may be employed. The oxygen is discharged from a cylin- 

 der of the gas, (provided with a reducing valve) through tubing con- 

 nected with a T-piece. To one limb of the T a small rubber bag is at- 

 tached, and the other is furnished with a small mica valve and ends 

 in the face mask. The valve does not open on expiration, so that oxy- 

 gen only collects in the bag, and it is inhaled on inspiration. The ap- 

 pliance is simple and saves oxygen, but patients not infrequently ob- 

 ject to covering up of the face with the mask. 



A very satisfactory method is that of S. J. Meltzer, 71 in which a flat 

 metal tube (hollow tongue depressor) is connected by wide rubber tub- 

 ing to a very easily manipulated respiratory valve, beyond which is a 



