2i6 RESEARCH IN PROTOZOOLOGY 



extent of the elevation of the erythrocyte count by diarrhea — a 

 factor that often is overlooked. 



It is, perhaps, unnecessary for me to dwell upon the unreliability 

 of the prevailing methods of hemoglobin estimation. The factors 

 of error are as great as those affecting blood counts. The Sahli, 

 Dare and Tallqvist methods are, perhaps, the most commonly used. 

 None is entirely satisfactory. The principle of the Dare instrument 

 is good, but I have found inaccuracies in the depth of the pipette, 

 an account of which I have published (1929). Ideally, we should 

 use some such method as that of Van Slyke (1918, 1921), but it 

 is too involved for use in a long series of cases unless special 

 study of the blood is being made. Probably the best method for 

 work of this kind is that of Newcomer. If the color disc is cor- 

 rectly standardized this is an extremely accurate method. The 

 proportion of hemoglobin present always should be recorded in 

 grams per 100 c.c. of blood — not by percentage. Whatever method 

 of hemoglobin estimation is selected should be used throughout 

 the work. The study of the blood in such problems could scarcely 

 be considered to be complete without resort to blood chemistry in 

 appropriate cases. The significance of ionic calcium deficiency in 

 sprue is at present very uncertain, and it is my belief that further 

 investigation is desirable. 



All work on the blood should be done by a person of wide ex- 

 perience in hematology — not a student, nurse or technician. I 

 would urge, also, that all blood estimations be made with apparatus 

 of known accuracy. 



TJie Urine. It should receive a thorough general examination. All 

 determinations should be made on a 24-hour specimen. The usual 

 general examination should include qualitative tests for indican 

 and urobilinogen. It is recommended that the student consult the 

 papers of Rowntree, Hurwitz and Bloomfield (1913) and of Flem- 

 ing (1926). Further work on the urine will be guided by the 

 nature of the case. 



In special cases it may be desirable to determine the basal 

 metabolism of the subject, especially after long residence in the 

 tropics. Fleming's observations (1925) will be found suggestive 

 here. The clinical man will employ the sigmoidoscope and the 

 Roentgen rays as occasion arises. It would be inappropriate to do 

 more than mention these measures here. 



Investigations of this kind naturally focus around the intestinal 



