THE SEMEN. 201 



Jacob! succeeded in fertilising the ova of a carp with 

 semen which had been contained within the body of the fish 

 for four days ; but it is well ascertained that the spermatozoa 

 of fishes in general live for a much longer period than that 

 named. * Some have supposed that the only use of the sper- 

 matozoa is by their movements to hasten the advance of the 

 semen towards the Fallopian tubes. 



PATHOLOGY OF THE SEMINAL FLUID. 



The quantity of seminal fluid secreted varies greatly accord- 

 ing to the age and constitution of the individual. In young 

 men, and in those whose health is vigorous, the secretion is 

 rapid and abundant ; in the aged, and in those whose vital 

 powers are feeble, it is but slow and scanty. It is, however, 

 in severe states of disease that the amount of seminal fluid 

 secreted is greatly diminished, if the formation of it be not 

 in some cases altogether suspended for a time. Under the 

 influence of recovery, the quantity of semen formed again 

 undergoes an augmentation. 



An inordinate secretion of the seminal fluid, as also its 

 prolonged retention in the testes, are sometimes the causes of 

 involuntary seminal discharges, which, however, are more fre- 

 quently occasioned by organic-weakness, the result of over in- 

 dulgence. 



If these emissions be very frequent, the ejaculated semen 

 will be found to be thin and watery, and to contain com- 

 paratively few spermatozoa. 



It is unnecessary to describe here the destructive effects of 

 these emissions on the constitution. 



It is often a matter of great importance to determine, in- 

 dependently of any revelation on the part of the patient, 

 whether in any particular case seminal effusions exist. 



This fact, ic is in the power of the microscope, according to 

 some observers, in all cases to declare with the most absolute 

 certainty. 



* Several most interesting particulars in reference to artificial im- 

 pregnation are given in Wagner's Elements, chap. iii. 



