602 MEALS MEDICINAL. 
in a tub covered lightly for three days, afterwards strained, and 
poured into bottles, which are to be kept uncorked until manifest 
fermentation has ceased ; each bottle must be full before it is 
corked. The infusion of Birch leaves is a reliable solvent of 
stone in the kidneys, even where other treatment by mineral 
waters, and drugs, has failed, so that a surgical operation seemed 
imperative. After taking the Birch tea for some while the 
stone has in each case begun to be dissolved, and has been 
passed by fragments in the urine. A teaspoonful of the 
powdered leaves is brewed in half a pint of boiling water 
for half an hour, this quantity being taken twice a day for 
six months continuously. Both the buds, and the young Twigs 
yield a volatile empyreumatic oil which is colourless, and 
volatile, having a pungent balsamic odour, the oil possessing 
a persistent fragrance of Russia leather; the bark affords 
‘betulin.” The fresh leaves are used to form a bed on which 
rheumatic patients lie, and which excites profuse perspiration. 
The oil is curative for skin eruptions, and for itch. “ Dis- 
putandt pruritus fit ecclesie scabies.” 
ROSEMARY. (See Herss). 
Ir has been already stated that an infusion of the dried Rosemary 
plant, (leaves, and flowers), being used when cold, makes one 
of the best hair-washes known ; its volatile oil specially stimulates 
the hair-bulbs to renewed activity. Physiologists (particularly 
M. Metchnikoff, of the Pasteur Institute,) now tell us why the 
hair becomes white as old age supervenes. Its pigment colour 
lies scattered, during early and middle life, between the two 
layers of each hair; whilst the hostile cells, or phagocytes, are 
all the time in subjection, because of the physical strength, and 
endurance then personally possessed. But in old age these 
hostile cells, which occupy the hairs’ central cylinder, gain the 
ascendency, and proceed to devour all the pigment within their 
reach, afterwards ejecting it from the body, and leaving the 
hair grey, or white. In like manner, as the years approach 
senility the higher nerve cells of the brain, which subserve 
intellectuality, sensation, memory, and control of movements, 
tend to disappear, and are replaced by elements of a lower kind, 
the superior nervous cells being devoured by these ‘‘ macrophags.” 
But the higher cells of the spinal marrow are much Jess subject 
