Self -Fertilization Induced by Artificial Means, 163 



been made several experiments on the action of solutions on the 

 spermatozoa of other animals. I find that there are quite a num- 

 ber of observations of this sort, although none of the observers 

 have had in view the same question with which I was especially 

 concerned. 



Kolliker in 1856 carried out an extensive series of experiments 

 on the effect of different solutions on the spermatozoa of the 

 bull, dog, rabbit, horse, and also made a few observations on the 

 spermatozoa from a human cadaver. He found that water alone 

 quickly brings spermatozoa to rest, but does not kill them. They 

 can be aroused to activity by adding, for instance, a 10 per cent, 

 solution of disodium phosphate.^ Many other substances were 

 found favorable to the activity of the spermatozoa, such as blood- 

 serum, sugar in certain strengths, sodium chloride, caustic pot- 

 ash, etc. 



The caustic alkalies (potassium, sodium, and ammonium hy- 

 droxide) were found to be especially powerful excitants. Kol- 

 liker also tried a number of other solutions, such as three different 

 kinds of sugar, glycerine, gum, etc., which in certain strengths 

 cause increased activity; also urea, gall, morphine, strychnine 

 (nitricum), which have an indifferent effect. He also tried al- 

 cohol, creosote, chloroform, ether, alkaloids, and tannin, which 

 have an injurious effect. Kolliker also examined the action of the 

 secretions of the glands of the male reproductive organs — the 

 uterus masculinus, prostate and Cowper's glands. He found 

 that these secretions excite the spermatozoa to greater activity.^ 



The much more recent experiments of Steinach bear even more 

 directly on the present problem. He found that after removal of 

 the glandulae vesiculares ("receptaculum seminalis" of some writ- 

 ers) of the male rat, that, although the sexual instinct remained, 

 the number of young that were born was much decreased. When 



1 Kolliker gives the formula 2Na0H0P0g, which is no doubt disodium 

 phosphate, now written Na HPO . 



2 Moleschott and Richetti are quoted by Kolliker as recognizing the favorable 

 action of sodium salts on the spermatozoa. Quatrefages found that the sper- 

 matozoa of the weasel showed a "surexcitation" in 64 parts sea water to one 

 part sea salt. Newport found that potassium carbonate, and also 1/480 of 

 potassium salt made the activity of the spermatozoa of the frog greater. 



