NEUTRON EFFECTS OK ANIMALS 115 



White Blood Cell Counts. Daily white cell counts were made by standard 

 procedure on blood obtained from the marginal ear vein. The counts for 

 most of the rabbits were made for 2-4 weeks prior to irradiation to establish 

 the individual normal value. 



Electrophoresis Measurements. Blood for electrophoresis was obtained 

 by heart puncture from animals from which food had been Anthheld over- 

 night to obviate plasma turbidity du? to fats. The 12 ml. sample of blood 

 drawn for each experiment was transferred to an oxalated tube and, after 

 gentle mixing to dissolve the solid oxalate, was centrifuged to obtain the 

 desired plasma. About 8 mg. of sodium oxalate per ml. of blood were 

 required to prevent clotting in some of the pathological samples, this 

 tendency to clot being due, apparently, to high fibrinogen contents. The 

 plasma was diluted -with phosphate-saline buffer to one-third its original 

 concentration and dialyzed in Msking tubing against 2 Hters of the buffer 

 for 48 hours at refrigerator temperatm-e. The buffer contained 5.76 ml. of 

 0.2:\I XaH2P04, 94.24 ml. of 0.2M Na2HP04 and 50 ml. of 3M NaCl in 1 

 liter of buffer solution, and was of pH 7.7 and of ionic strength 0.2. 



IMoving boundary electrophoresis experiments were made by means of a 

 standard Tiselius-Klett apparatus ^\'ith a single section, 11 ml. cell and at a 

 potential gTadient of 5 volt/cm. The relative concentrations of the plasma 

 components were determined from the measured areas under the various 

 peaks of the diagrams which were obtained by the enlargement of photo- 

 graphs, taken by the Longsworth scanning method (5), after electrophoresis 

 for 5 hours. The diagrams were divided into sections representing the 

 various plasma components by raising perpendicular lines from the baseline 

 to the lowest point between adjacent peaks (6, 7). Tracings of ascending 

 boundaries were used for calculation since a division between the "7" and 

 "5" peaks was more readily made on the ascending than on the descending 

 patterns. The areas under the "5" peaks were disregarded in the calcula- 

 tions of the percentages of the various plasma constituents. 



. RESULTS 



Since experiments were made on 36 rabbits, many of which were used in 

 confirmatory studies, representative data only have been presented 

 wherever possible. While in some instances electrophoresis runs were 

 made on plasma from rabbits for which the white cell study was unavailable 

 or incomplete, the reproducibihty of the effect of neutron irradiation on 

 white cell coimt and on plasma composition justified the inclusion of such 

 data. 



N'or7nal White Blood Cell Count. The count for any one rabbit was found 

 to vary considerably from day to day and, further, different rabbits were 

 found to have different average normal values. The magnitudes of these 



