3772
Streptomycin sulfate ( 300 mg / kg s . c . ) was injected for various periods into preweanling rats and for 3 weeks into weanling rats .
 Streptomycin
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Disease, Chemical 
Text: {0} 
Answer:
 Streptomycin