CHAPTER III 



77?^ Influence of Extraneous Factors, 

 Hormones, and Environmental Conditions 



Sperm inhibitors and spermicidal substances. Cliemical aspects of short- 

 wave radiation. Variations in hydrogen ion concentration and tonicity. 

 Influence of heat and cold; sperm vitrification and 'la vie latente'. Role of 

 hormones. Sperm-egg interacting substances and chemotaxis. 'Dilution 

 effect' and chemical changes associated with senescence. The use of arti- 

 ficial diluents in the storage of semen. 



The list of agents, both physical and chemical, which affect sperma- 

 tozoa, includes among others, changes in temperature, visible light, 

 short-wave radiation, atmospheric pressure, ionic strength, and a 

 host of pharmacologically active substances. The vast literature on 

 the subject of sperm activation and inhibition goes back as far as 

 Leeuwenhoek's observation that dilution with rain water deprives 

 the canine 'animalculi' of motion, and a report by his learned friend 

 Johan Ham of Arnhem, on the loss of sperm motility in a patient 

 dosed with turpentine. Among Spallanzani's contributions in this 

 field is the discovery that freezing in snow does not necessarily kill 

 the 'spermatic vermiculi' but reduces them to a state of 'lethargy' 

 from which they recover when returned to higher temperature. The 

 XlXth century abounds in studies on the effect of changes in the 

 medium on sperm motility and survival. Prevost and Dumas (1824) 

 extended Spallanzani's observations on the lethal effect of electric 

 shock and certain poisons; Donne (1837) investigated the influence 

 of milk, urine, and the vaginal and cervical secretions; de Quatre- 

 fages (1850, 1853) described in great detail the marked toxicity of 

 copper, lead and mercuric salts. Newport (1853) studied the nar- 

 cotizing influence of chloroform vapours on the amphibian sperma- 

 tozoa, and concluded 'that the spermatozoon does not impregnate 

 when entirely deprived of its power of motion by narcotization and 

 disenabled to penetrate into the envelopes of the egg'. Both Newport 



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