On Blood- Platelets. 



461 



Even in a normal animal a low count is obtained if, for some reason, a free 

 flow of blood cannot be established. 



Effect of Malnutrition Not Due to Vitamin Deficiency. — In order to study 

 this effect young rats of about 50 grm. weight were kept on a protein-free 

 diet, consisting of starch, salt mixture, and olive oil, to which the vitamins A 

 and B were added in the form of cod-liver oil and marmite. As a result the 

 rats decline in weight, but remain otherwise in good health, for three or four 

 weeks. The platelets show no diminution at a time when the animals have 

 lost 10 grm., i.e., 20 per cent, in weight, as the following figures show : — 



Effect of Protein Deficiency in the Presence of Vitamins. 



No. of 

 rat. 



Weeks of 



protein 

 deficiency. 



Temperature. 



Loss in 

 weight. 



Red cells. 



Platelets. 



420 



3 



o 



38 '4 



10,? 



9,776,000 



1,060,000 



421 



3 



38 -3 



1Q? 



9,280,000 



930,000 



422 



3 



38 -3 



lOg 



10,370,000 



1,230,000 



Effects of Exposure to Radium. 



It is well known that a profound lymphopenia can be produced and main- 

 tained by relatively small doses of ft or 7 radiation. With larger doses 

 additional blood changes occur : first a diminution in the number of poly- 

 morphs and with still larger doses a reduction in the number of red cells and 

 haemoglobin content. For instance, when rats were continuously exposed to 

 radium under constant conditions, a lymphopenia occurred within a few 

 hours, a polymorpho-leucopenia in 7 days and an anaemia in 13 days. 



Examples of these effects are given in Protocols Nos. 1 and 2. 



Protocol No. 1 showing changes in the polymorphs : — 



Three male rats : weights 150, 160, 155 grm., exposed continuously to 

 220 mgrm. EaBr 2 , 2H 2 0, distance 8 inches, screen - l mm. lead, - 12 mm. 

 silver, for 7 days — this is equivalent to 0'55 rads. 



Two control rats : weights 210 and 165 grm. 



Protocol No. 2 showing changes in red cells and haemoglobin. Three female 

 rats : weights 80, 85, 75 grm. exposed, continuously to radium, as in Protocol 

 No. 1, for 13 days, equivalent to 1*2 rads. 



Three control female rats : weights 80, 85, 75 grm. 



