126 University of California Publications in Zoology [Vol. 19 



THE THERAPEUTIC VALUE OF BISMUTH SUBNITRATE 



AND BISMUTH SALICYLATE IN THE TREATMENT 



OP GIARDIASIS (LAMBLIASIS) OF RATS 



Introduction 



The use of these two salts in the chemotherapy of giardiasis of 

 man was attended with some success in England and consequently 

 encouraged further treatments with these same chemical compounds 

 in order to ascertain their true therapeutic value. 



The account of the bismuth treatments of giardiasis of man was 

 given by Porter (1916), who made an enumerative study of the cysts 

 of Giardia intestinalis occurring in the stools of dysenteric patients. 



Procedure 



Finding a large number of rats infected with G, microti, a species 

 similar to G. intestinalis (the history of which was followed for a 

 period of one month by daily faecal examinations) six were selected 

 which showed the heaviest infection. The degree of infection was 

 determined by the number of positive examinations of the faeces made 

 daily during the month. Three of the rats were treated with bismuth 

 sub-nitrate and the other three with bismuth salicylate. 



It was found that the best way to administer the dose is to spread 

 the salt (powder) on water-soaked bread each day. The rats then ate 

 the bread at the same time, receiving approximately a full dose of the 

 salt. The rats did not object to the treatment, although at different 

 intervals they appeared very nervous, slow in movement, often sluggish, 

 to some degree ferocious, and their coats manifested a certain degree 

 of roughness. Periods of constipation also occurred, and in the 

 case of one rat no faeces were defaecated on one day. Otherwise 

 constipation was indicated by the defaecation of very small pellets. 



As has been said previously, a history of the six rats was known 

 throughout a period of about a month. Table 4 shows the degree of 

 infection of each rat for each day during a period of twenty-eight 

 days when daily examinations had been made of the faeces. The 

 number in each square represents the number of cysts counted for that 

 day in any twenty fields of the microscope by the use of a one-inch 

 ocular and four-millimeter objective. A negative sign in the square 

 means that no cysts were detected in the stools for that day. 



