MANOMETRIC AND GASOMETRIC METHODS 297 



constitutes normal (100%) hemoglobin (with different hemoglobinometers 

 100% may mean anything between 13.8 and 17.3 g. hemoglobin per 100 ml.), 

 and in any case this varies with sex and age. Values should, therefore, be 

 given in grams hemoglobin per 100 ml. blood, not in per cent hemoglobin. 



It is impossible and inadvisable to recommend one method of 

 hemoglobinometry as ideal. The choice will depend a great deal on 

 the availability of special apparatus and the training of the analyst 

 (c/. here the remarks of Holden, 1317). Since diurnal variations in 

 the hemoglobin content of one individual have been found, high 

 precision is hardly needed in a method for clinical routine estimation. 

 If carefully handled, a less exact method with simple apparatus may 

 give more reliable results than one involving elaborate apparatus in 

 the hands of a worker insufficiently trained in its use. It should be 

 noted that cloudiness produces more serious errors in photoelectric 

 and spectrophotometric estimations than in colorimetry, hence con- 

 trol measurements in a wavelength region of low absorption are 

 advisable. 



In order to improve clinical hemoglobinometry, the first task should 

 be the standardization of all instruments by a laboratory particularly 

 equipped for the purpose. Secondly, it should be recognized that 

 hemoglobin estimation requires sound biochemical and physical train- 

 ing of the worker, as well as careful interpretation of the result by 

 the doctor. Thirdly, there appears no reason why better, though 

 somewhat more expensive, apparatus should not be used in this, one 

 of the most commonly used and most badly neglected biochemical 

 estimations. Exact estimations of hemiglobin and sulfhemoglobin, 

 which are of importance in certain ca-ses, cannot be carried out with- 

 out such instruments. The hematologist should in any case have 

 experience in spectroscopy and should be able to detect the presence 

 of hemiglobin and sulfhemoglobin and to distinguish between them. 



9.2. Manometric and Gasometric Methods 



The manometric method is exact, but requires special apparatus 

 and a good deal of experimental skill and is time consuming. It is 

 therefore the ideal method for standardization of instruments or for 

 research purposes rather than for clinical estimation. A simple 

 microgasometric method, particularly suitable for the estimation of 

 carboxyhemoglobin has been developed by Roughton and Scholander 

 {2369,2370,21^59). The manometric and gasometric methods have 



