COLLECTION OF BLOOD. 175 



stain, or by eosin and methylene blue used separately ; 

 the parasites are stained pale blue and the corpuscles 

 bright red. 



A simpler stain is that recommended by Rees (Prac- 

 titioner, March, 1901) involving the use of carbol-thionin 

 prepared by dissolving 1-5 grammes of thionin in 10 c.c. 

 of absolute alcohol and 100 c.c. of a five per cent, 

 solution of carbolic acid. This is to be kept for at least 

 a fortnight and diluted with four times its bulk of dis- 

 tilled water immediately before use. Staining is com- 

 plete in about ten minutes. Ordinary carbol-thionin 

 answers very well indeed. Thionin stains the red 

 corpuscles a faint green, nuclei blue, and the parasites 

 an intense purple. 



In a suspected case of malaria the search should not 

 be abandoned in less than half an hour, or, in the case 

 of an inexperienced observer, much longer. 



A fuller description of the parasite and the differences 

 between the forms which are present in the various 

 forms of the disease is beyond the scope of this work, 

 and the reader is referred to the admirable special 

 number of the Practitioner mentioned above. 



COLLECTION OF BLOOD FOR EXAMINA- 

 TION BY CULTURAL METHODS. 



This is a much more difficult matter and should not 

 be attempted unless and until the film method has 

 failed. The difficulty arises from the abundant bac- 

 terial flora of the skin ; unless the most thorough 

 antiseptic precautions have been taken the results are 

 absolutely useless. They are worse than useless, they are 



