136 THE BLOOD. 



the filter has ceased to drip, it is weighed, and the weight of 

 the albumen ascertained by deducting the weight of the filter. 

 The proportion of albumen to 1,000 parts of blood is obtained 

 by the following formula : 



Serum used : Albumen : : Serum per 1,000 : Albumen 

 per 1,000. 



The above process, which has been described in detail in 

 the hope that it may be employed by others in analysis of 

 the blood for its organic constituents, has at least the advan- 

 tage of simplicity and facility of application. As regards 

 accuracy, having repeatedly made analyses of different por- 

 tions of the same fluid with almost identical results, it has 

 seemed sufficiently exact for all practical purposes. As an 

 example we may mention an analysis of two equal portions of 

 defibrinated blood (34*20 grammes) for corpuscles ; one speci- 

 men gave 16*4:0, and the other 16*43 grammes. This part of the 

 process would seem more open to the objection of inaccuracy 

 than any, yet the difference of the result in the two analyses is 

 so slight that it may be disregarded. Repeated examinations 

 of different specimens of the same serum for albumen were 

 followed by identical results. 1 While the exceeding accu- 

 racy which is desired by chemists, and is necessary in many 

 analyses, is not attainable in such examinations as these, it is 

 not even desirable ; for as physiologists we must see that 

 even an approximation of the proportions of the organic 

 matters, as they really exist, is better than the most accu- 

 rate estimate of their dry residue. In taking the weights, 

 the only point is to do it rapidly and avoid loss by evapo- 

 ration. If this be borne in mind, and care be taken in differ- 

 ent examinations to weigh the principles at the same stage 

 of the operation, the simplicity of the process should make it 

 valuable in comparative analyses of the blood in different 

 conditions of the system. 



In estimating the proportion of fibrin, the ordinary 



1 American Journal of tlie Medical Sciences, loc. cit. 



