X,B,3 Barber et al.: Malaria in the Philippines 197 
which was introduced by Ross § and employed by Koch ® in the 
examination for trypanosomes, has found favor with many in- 
vestigators of malaria. It was modified by Ruge*® and employed 
by Dempwolf." 
Dempwolf reports on malaria examinations in Daressalam, in 
which examinations by the thick and the thin smears are com- 
pared. Summarizing all cases, which include children and 
adults, quinine treated and untreated, and various nationalities, 
9,758 examinations by the thin-smear method gave 8.5 per 
cent positive, while 5,770 examinations by the thick-film 
method gave 25.7 per cent positive. In this method the unfixed 
thick film was dried for from two to twenty-four hours, then 
a mixture of 2 drops of Giemsa stain to 2 cubic centimeters of 
water was poured on the slide and allowed to remain for from 
fifteen to twenty minutes.. The slide was then rinsed and dried. 
The author recommends the thick-film method for the exam-- 
ination for blood parasites where large numbers of persons must 
be examined. 
James 12 made use of the thick-film method. He first laked 
out the hemoglobin in ethyl alcohol plus a small percentage of 
hydrochloric acid (10 drops of commercial hydrochloric acid 
to 50 cubic centimeters of alcohol) fixed to the slide, washed 
the slide for from ten to fifteen minutes in running tap water, 
dried it in the air, and then stained with any good modification 
of the Romanowski method, such as Hastings’s, Wright’s, or 
Leishman’s. The stain in liberal quantity was put on the slide, 
allowed to remain two or three minutes to fix, then diluted with 
all the distilled water that the slide would hold. After a few 
minutes he diluted again and after five minutes often made a 
further dilution. The stained slide was washed in tap water. In 
100 cases of malaria in the Canal Zone he obtained 94 per cent 
positive by the thick-film method where the thin-film method of 
the same cases gave only 60 per cent positive. The time of 
examination was limited to five minutes for the thick films from 
each* patient. By the thick-film method he was able to demon- 
strate parasites in quinine-treated cases, on the average, three 
days after the beginning of the treatment, even in latent or 
scanty infections. 
* Rept. Thompson Yates Lab. (1903), 5, part I. 
® Deutsch. Med. Wochenschr. (1907), 1889. 
* Malariakrankheiten, 2 Aufl. (1906), 290. 
* Arch. f. Schiffs- u. Tropenhyg. (1908), 12, 485. 
* Proc. Canal Zone Med. Assoc. (April to September, 1911), 4, pt. I, 49. 
