ix THE SKIN AND CUTANEOUS GLANDS 515 



Laffoiit (1879), on repeating Kohrig's experiments on curarised 

 goats, came to the opposite conclusion, viz. that the milk secretion, 

 like many other secretions, is under the simultaneous control of 

 secretory and of vaso-dilator nerves. 



Hammerbacher (1884) studied the effect of pilocarpine and 

 atropine injection on the lacteal secretion of the goat. In animals 

 kept on a constant diet, he found that subcutaneous injection of 

 3-15 cgrms. pilocarpine caused no perceptible increase in the milk 

 secretion, while a few 'hours after injection of large doses of this 

 drug the secretion was reduced, and the milk also contained fewer 

 solids. 



Atropine, on the contrary, even in small doses diminishes the 

 secretion of milk, while tl^e content of solids, particularly the 

 percentage of fat, was much increased. This effect of atropine is 

 borne out by the clinical fact that it is successfully used to stop 

 the secretion of milk in nursing women. 



Valentowicz (1888), who continued Kohrig's experiments on 

 goats, found that the stimulation of the peripheral end of the 

 external spermatic diminished the secretion instead of increasing 

 it. But after dividing this nerve on one side, the difference in 

 the amount of secretion, and also in the composition of the milk 

 on the two sides, is not very marked. He noted, however, that 

 after some time there was a certain increase in the amount of milk 

 secreted and the fat content, on the operated side (paralytic 

 secretion). If milking was discontinued in both udders for several 

 days and then resumed, the secretion was found to be much less 

 in the normal mamma than in that of which the nerve had 

 been cut out. He concluded that the external spermatic nerve 

 (as a whole) is an inhibitory nerve for the milk secretion. 



To us the experiments of Mironow (1894), also on goats, seem 

 more important. He wished to confirm, the clinical fact that 

 sudden excitation of the nervous system and sharp mental 

 emotions diminish or temporarily suppress the function of the 

 mammary gland in nursing women. The milch goat was kept 

 on a constant diet, and milked twice a day so as to reach a certain 

 maximum of secretion. On the day before the experiment and 

 after obtaining this result, the goat was milked every 2-3 

 hours from the morning till night. The same 2-3 hours' milking 

 was repeated on the day of the experiment, but on that day a 

 sensory nerve to the hind leg (the saphenous nerve) was exposed, 

 raised by a thread, and excited with an induced current of increas- 

 ing strength for 30-60 minutes, on which the animal showed 

 symptoms of acute pain, agitation, tachypnoea, etc. 



In twenty-four experiments of the same kind, on different goats, 

 Mironow invariably obtained a considerable diminution in the 

 secretion of the milk, for a longer or shorter time, in direct relation 

 with the intensity and duration of the pain. 



