sterility . 195 



spermatozoa are present, they will be observed as 

 small swiraming tadpole -like organisms. Should the 

 spermatozoa be absent, or should the fresh speci- 

 mens be inactive, the trouble is clearly located in the 

 spermatic fluid, which is formed in the testicle. It 

 is very rare for males ever to recover their fertility 

 if the spermatozoa are not found in the spermatic 

 fluid. Sometimes, however, this absence is due to 

 some temporary disorder, which " can be removed. 

 Abnormal growths and diseases of the genital sj'Stem 

 in the male must be dealt with according to circum- 

 stances. In such cases it is frequently an economical 

 plan to castrate the animal and fatten him for the 

 market. 



Sterility in the female may be due to an absence, 

 or to an abnormal condition, of the ovum, or egg, 

 which develops in the ovary and is discharged into 

 the uterus or womb periodically at the time of "heat." 

 These conditions are not frequent, however, as those 

 animals which come in heat regularly and with the 

 normal symptoms are usually fertile, so far as the 

 egg is concerned. It is difficult to determine when 

 sterility is due to an absence, or to sterilitj^ of the 

 egg -cell. 



Another cause of sterility in the female is an altered 

 secretion of the mucous membrane which lines the 

 genital organs. If this secretion be acid in reaction, 

 it is fatal to the male cells, or spermatozoa. The 

 mucous membrane may be diseased, and this condition 

 ma}' cause sterility. In some animals, especially cows, 

 there is often observed a disease, known as nymphomania, 



