890 THE PHYSIOLOGY OF REPRODUCTION. 



or by way of the circulation. There are indications that the 

 secretion of the mammary glands is under the control, to some 

 extent at least, of the central nervous system. For instance, in 

 women during the period of lactation cases have been recorded 

 in which the secretion was altered or perhaps entirely suppressed 

 by strong emotions, by an epileptic attack, etc. This indication 

 has not received satisfactory confirmation from the side of ex- 

 perimental physiology. Eckhard found that section of the main 

 nerve-trunk supplying the gland in goats, the external spermatic, 

 caused no difference in the quantity or quality of the secretion. 

 Rohrig obtained more positive results, inasmuch as he found that 

 some of the branches of the external spermatic supply vasomotor 

 fibers to the blood-vessels of the gland and influence the secretion 

 of milk by controlling the local blood-flow in the gland. Section 

 of the inferior branch of this nerve, for example, gave increased 

 secretion, while stimulation caused diminished secretion, as in the 

 case of the vasoconstrictor fibers to the kidney. These results 

 have not been confirmed by others in fact, they have been sub- 

 jected to adverse criticism and they cannot^ therefore, be ac- 

 cepted unhesitatingly. 



After apparently complete separation of the gland from all its 

 extrinsic nerves, not only does the secretion, if it was previously 

 present, continue to form, although less in quantity, but in opera- 

 tions of this kind upon pregnant animals the glands increase in size 

 during pregnancy and become functional after the act of parturi- 

 tion.* This result confirms the older experiments of Goltz, Rein, 

 and others, according to which section of all the nerves going to 

 the uterus does not prevent the normal effect on lactation after 

 delivery. Regarding the question of the existence of secretory 

 nerves, Baschf reports that extirpation of the celiac ganglion or 

 section of the spermatic nerve does not prevent the secretion, but 

 causes the appearance of colostrum corpuscles. 



Experiments, therefore, as far as they have been carried in- 

 dicate that the gland is under the regulating control of the cen- 

 tral nervous system, either through secretory or more probably 

 through vasomotor fibers. The bond of connection between the 

 mammary gland and the uterus is, however, established mainly 

 through the blood rather than through the nervous. system. Some 

 direct evidence for this point of view is furnished by the interesting 

 experiments of Starling and Lane-Claypon.J These authors found 

 that extracts made from the body of the fetus, or rather from the 



* Mironow, "Archives des sciences biologiques, " St. Petersburg, 3, 353, 

 1894. 



t Basch, "Ergebnisse der Physiologic," vol. ii., part i, 1903. 



J Lane-Claypon and Starling, "Proceedings of the Royal Society," 1906, 

 B. Ixxvii.; see also Starling in "Lancet," 1905. 



