58 INTRODUCTION TO SEXUAL PHYSIOLOGY 



this contention Maclit and Lorbin have recently obtained evidence 

 of the existence in the blood of a menstrual toxin which exudes 

 in the sweat and other secretions and has a deleterious effect on 

 living plant tissues. Thus they state that a flower held in the 

 hand of a menstruating woman will wither more rapidly than 

 otherwise, owing to the action of this toxic substance which is 

 not present excepting at this stage in the cycle. The menstrual 

 toxin is believed to affect the milk in lactating women, children 

 sucking at such times being liable to slight digestive disturbances. 

 A similar belief has been held about the milk of sows at the heat 

 periods, the young pigs being said to develop diarrhoea or other 

 alimentary troubles. 



Menstruation, however, is often in abeyance during suckling 

 (according to Fordyce, in about 60 per cent, of cases). The 

 non-recurrence of menstruation is called amenorrhoea. It may be 

 due to some pathological condition or to anaemia, arising some- 

 times from underfeeding. Fraenkel reported that it was common 

 in Germany during the Great War, when it resulted from 

 malnutrition, overwork, and general strain. A condition of 

 amenorrhoea is said to occur normally in Lapland and Greenland 

 during the winter, when it is clearly comparable to the anoestrum 

 of animals. 



Menstruation, as the name implies, recurs on the average 

 in non-pregnant women every lunar month of about twenty- 

 eight days. The cycle may, however, vary a good deal from 

 this, and without any impairment of health ; thus it is sometimes 

 five weeks and occasionally as short as two weeks. 



Puberty and the Climacteric 



The first occurrence of menstruation marks the age of puberty. 

 This in temperate climates occurs in girls at from fourteen to 

 fifteen, or about a year earlier than puberty in boys. Li the 

 races inhabiting warm or tropical countries, puberty is attained 

 about two years earlier. The variation is largely racial, but 

 partly the direct effect of environment. Luxurious living tends 

 to hasten puberty, while inferior conditions, poor diet, and over- 

 work may retard it. 



At puberty ripe ova and spermatozoa are produced for the 

 first time, and the gonads undergo enlargement. Li correlation 



