INTERNAL SECRETIONS OF SEXUAL GLANDS 



99 



female by which the male is attracted, and the clasp reflex is 

 kept up by the continuous stimulation of the above-mentioned 

 parts of the skin. According to Goltz there is also a reflex 

 dilatation of the seminal ducts and a reflex ejaculation. Goltz 

 supposed that the spinal cord and the sensory organs in the 

 skin are, during heat, in a state of increased irritability. 



Since Goltz' time many experiments have been performed 

 to determine the role played by different parts of the central 

 nervous system on the clasp reflex. All these experiments 

 have shown that the mechanism of this reflex is a much more 

 complicated one than Spallanzani and Goltz supposed. 



Alhertoni (1887, 1889) and Tarchanoff (1887) showed that 

 the clasp reflex in toads and frogs can be 

 inhibited by stimulation of the corpora bigemina 

 {Fig. 50). Schrader (1887) concluded from experi- 

 ments on the frog that centres inhibiting the 

 clasp reflex are to be found also in lower parts of 

 the brain, such as the cerebellum and the upper 

 portion of the medulla oblongata. The later 

 experiments of Busquet (19 10), Steinach (19 10), 

 and Baglioni (1912) afforded a more detailed 

 knowledge of this question. Busquet separated 

 the spinal cord from the brain in the frog by 

 an incision just below the medulla oblongata, 

 outside the time of heat. By touching the skin 

 of the breast, or by laying the operated animal Brain of frog 

 on another frog, the clasp reflex may be evoked, 

 and may persist for several hours. This experiment may 

 be successful at any time of the year. Busquet performed 

 200 of these experiments with success. The reflex can be 

 evoked for about a week after the operation, i.e., as long 

 as the animal survives. Similar results may be obtained 

 after decapitation or a strong blow on the head. Evidently 

 outside the time of heat certain impulses from above the 

 spinal cord inhibit the clasp reflex, and we must suppose 

 that the hormones produced by the sex gland during heat 

 lower the irritability of these inhibiting centres. According 

 to Busquet, this nervous mechanism is present only in the 

 adult male; in 200 females Busquet never could evoke the 

 clasp reflex after the operation mentioned above. Further, 

 Busquet tried to show that this nervous mechanism develops 



Corp. bi^. 



med. obi. 



Fig. 50. 



