2O2 EDWIX J. COHX. 



X. THE EFFECT OF BEEF BROTH UPON THE ACTIVITY AND UPON 

 THE LONGEVITY OF SPERMATOZOA. 



Gemmill showed that the length of life of spermatozoa could 

 be increased by adding beef broth to sea water. He believed 

 that this brought about the "keeping alive of spermatozoa by 

 artificial nutrition" (Gemmill, J. F., 1900, p. 171) (see p. 178). 



The work of Gemmill has been repeated and his observation 

 that sea water to which beef broth has been added in appropriate 

 concentration prolongs the life of spermatozoa, confirmed. The 

 activity of spermatozoa, however, is decreased in the beef broth 

 suspensions. Moreover the addition of beef broth to sea water 

 increases the hydrogen ion concentration. 1 



It is unfortunately not possible to neutralize the suspension 

 without throwing down a heavy precipitate. 2 This brings about 

 such changes in the ionic composition of the sea water as to make 

 uninterpretable the results of experiments carried out in such a 

 medium. 



The protocols of two experiments that confirm the results of 

 Gemmill are recorded. 



2.5 grams of Armour's "extract of beef" were dissolved in 290 

 c.c. of sea water, making the concentration by weight approxi- 

 mately 8.6 per cent. The suspension of beef broth in sea water 

 was acid to neutral red. That is, the hydrogen ion concentration 

 was greater than Ph 6.5. Diluting the suspension at once de- 

 creased its concentration in beef broth and in hydrogen ions. 

 The hydrogen ion concentrations were not directly determined, 

 but their approximate value has been calculated from the num- 

 ber of cubic centimeters of o.oiN NaOH required to make them 

 alkaline to phenolphthalein. 



To 10 c.c. of the different concentrations of acid broth one drop 

 of dry sperm was added. Tests were made by adding one drop 

 of each sperm suspension to five drops of eggs in 10 c.c. of sea 

 water. The percentage of eggs that were fertilized are reported 

 in Table XIII. 



1 The increase in viscosity of the suspension, and also the increase in protein 

 content, may be effective in decreasing the activity of spermatozoa. 



2 In all probability an insoluble calcium salt or aggregate. 



