LEUKAEMOGENIC EFFECT 



29 



research, Mt. Vernon, N.Y.); solution for injection: 100;u,c/ml in saline for 

 first injection, 200/xc/ml for second and third injections). 



Grouj) V (32 animals) was given three subcutaneous injections of ^H- 

 cytidine at weekly intervals (3 x lO/tc/g body weight, based on average 

 weight of each cage. Specific activity 1 c/m mole (Schwarz Bioresearch, Mt. 

 Vernon, N.Y.); solution for injection: lOO/xc/ml in saline for first injection, 

 200 ^c/ml for second and third injections). 



Group VI (32 animals) received three subcutaneous injections of both 

 ^HTDR and ^HCR at weekly intervals (dosage as in Group IV and V). 



Group VII had no treatment. 



The animals were allowed to die spontaneously or were killed in a definite 

 moribund state. 



EESULTS 



During the first months after initiation of the experiment, some animals 

 of each group (19 out of 224 in total) developed ulcerative skin lesions due to 

 mites around the base of the tail. These mice were then kept in separate cages. 

 All animals were given two successive dipping treatments at an interval of 2 

 weeks in a solution of 2% Aramite and 0-1% Nacconal in water. By this 

 procedure, the skin lesions were prevented from spreading to the colony in 

 general. 



The animals that died spontaneously or were killed in a moribund state 

 are listed in Table I. Except for Groups I-III all mice dymg showed generalized 



Table I. Number of mice killed in moribund state or dead ivith or without thymic 



lymphoma 



Group 



Number of mice killed in moribund state or dead 



(Days after start of experiment) 



Number of t^ . , ^ o ^ ,^ ^ ,„ ^ 



animals -Lreatment J ^^g^ IS^gg^^l 



lO lO C- rt I I I I I I 



C-l I I I -H O ■— I CO >-H CO 



ICOl— ICOO (MiOt^OfM 



r-i <M lO t- p— I ^ rt I— I CI (M 



3 X 160 r ____!** 1** _ 1** 1** i-j- 



1* 



3 X 160 r — — — — — — _ 3** 2** 2** 



3 X 160 r — — — — — ^ 2** 3** 2** — 



3 X 3HTDR ____!* 1* ____ 



3 X 3HCR ____!* 1* ____ 



3 X »HTDR+ _ — __l* 1* ____ 



3HCR 



None — — — — 1* — — — — — 



32 



VIT 



32 



* Dying with skin lesions and generalized infection. 

 ** Dying with thymic lymphoma. 

 "f" Dying with mammary gland carcinoma. { See text. 



