Mar. i,i92i Effects of X-rays on Trichince 851 



SERIES IV 



Under date of June 28, the roentgenologist states that the meat used 

 in this series of experiments was — 



exposed to the direct action of the rays at a distance of very nearly 2 5 cm . from the 

 focal spot of a Coolidge-type tube. The pressure across the tube terminals was 73 

 kilovolts, measured by standard sphere gap, and also by ratios. The current through 

 the tube varied during the time of treatment, which extended over a period of about 

 3 hours. The lowest reading was 4.2 milliamperes, the highest 4.9. This high 

 reading, however, was for only a short time after the tube was started. The current 

 gradually dropped during 10 minutes to 4.3 milliamperes, and during the rest of the 

 treatment fluctuated between 4.2 and 4.3 milliamperes. 



The boxes were so placed that the rays from other tubes in the machine had very 

 little influence on the contents. By calculation it shows as negligible . 



Box A was given an exposure of 42 minutes ; box B an exposure of 84 minutes ; box C 

 an exposure of 126 minutes; and box D an exposure of 168 minutes. Following the 

 system of measurement used by Davey, 1 which has the merit of being a complete ex- 

 pression of X-ray quantity, these dosages would read: 



MAM 

 Box A 1S0 — at 73 KV. 



25- ' J 



Box B 361 ^^at 73 KV. 



13 n MAM f vxr 



Box C 542 — — at 73 KV. 



MAM 

 Box D 722 g - at 73 K\ . 



The rats used in this series of experiments were fed on July 31 and 

 August 3. Five rats were fed in each experiment. 



Experiment 16 (box a), 42 minutes. — Rats 1 and 2 died August 4. 

 A few trichinae were found in the intestines. The parasites showed evi- 

 dence of growth. The sex cells were strikingly disorganized. Other 

 organs also showed evidence of injury. Rat 3 was killed on August 20; 

 diaphragm moderately infested. Rat 4 died on August 29; diaphragm 

 moderately infested. Rat 5 died on September 16; diaphragm moder- 

 ately infested. 



Experiment 17 (box b), 84 minutes. — Rat 1 died on August 6; intes- 

 tines negative. Rat 2 died on August 1 7 ; intestines and diaphragm neg- 

 ative. Rat 3 died on August 18; results same as in rat 2. Rat 4 died 

 on August 20; results same as in rat 2. Rat 5 was killed on September 

 10; diaphragm negative. 



Experiment 18 (box c), 126 minutes. — Rats 1 and 2 were killed on 

 August 20; diaphragms negative. Rats 3 and 4 were killed on Septem- 

 ber 10; diaphragms negative. Rat 5 was killed on September 10; dia- 

 phragm slightly infested. 



• Davey (op. cit., p. 586) states: " The voltage and distance are given directly and the product of the cur- 

 rentandtimeis given, thus, 'ioomilliampere-minutesat 25 cm. distance at 50 kilovolts.' This is usually con- 

 tracted to read ioo^ 1 ^- 1 tt 5 okv. It will be noticed that distance is expressed in terras of its square. 

 This is because the intensity of X-rays varies inversely as the square of the distance. 



