/ 



Rickets in Rats. 195 



by the introduction of 04 per cent, of potassium phosphate, 

 (Diet 85) rickets was prevented. Here again growth in body 

 weight was practically suspended, but the addition of potassium 

 phosphate to the diet resulted in an increased assimilation of 

 calcium so that together with absence of bone lesions there was 

 found a percentage of calcium in the body somewhat higher than 

 the normal average for the age, though naturally in view of the 

 marked stunting of the animals the absolute amount of calcium 

 in the body was less than in a normal rate of the same age (which 

 would have had at least twice the body weight). 



Our pathological findings are summarized in Table I. 



TABLE I. 



Summary of Findings as Regards Rickets. 



Diet No. 



Composition of Diet. 



Total Number of Rats Examined. 



A. Rachitic. 



B. Non rachitic. 



83 



Calcium lactate 



Sodium chloride 



...95% 

 ... 3% 

 ... 2% 



2 



0 



84 



Patent flour 



Calcium lactate 



Sodium chloride 



Ferric citrate 



...95% 

 ... 2.9% 

 . .. 2.0% 



... 0.1% 



13 



• 



80 



Patent flour 



Calcium lactate 



"Sodium chloride 



Potassium phosphate 



Ferric citrate 



...95% 

 ... 2.5% 

 . .. 2.0% 

 ... 0.4% 

 ... 0.1% 



0 



15 1 



In our observations as summarized in Table I, the diagnosis 

 of rickets has been based upon the microscopic examination of ribs 

 and femora, partially decalcified in Mueller's fluid; and in several 

 instances, confirmed by X-ray examination. The histological 

 criteria are: (1) the great increase in width of the zone of growing 

 cartilage, and its irregular projection towards the diaphysis; (2) 

 the failure of calcium deposition in the zone of preparatory 

 calcification; (3) a pronounced increase in the osteoid margin, 

 both in the region of the metaphysis, and along the shafts of the 

 bones. 



1 s of these placed on special diet at age of 60 days; i at 81 days; all remain- 

 ing animals started at four weeks of age. 



