724 SUMMARY OF CURRENT RESEARCHES RELATING TO 



Repeat this with as many sections as desired, or until the bottle is 

 rilled. In case tho parcels do not fill the bottle, completo it by a 

 wad of tissuo paper. Tho bottlo may then bo posted as usual by 

 boring a holo in a block of wood and packing with paper. The 

 sections aro, of course, removed on reaching their destination by 

 unfolding tho parcels in alcohol and floating off the specimens. 



In the caso of very delicate sections it is well to float them into 

 paraffined paper or writing paper ; straighten out the folds of the 

 section by holding tho folded portion in alcohol and manipulating it 

 with a small red sable brush; then cut away the uncovered portions 

 of tho paper and pack as before. 



Polarized Light as a means of recognizing Irritable Conditions 

 of the Nerves of the Scalp. * — Dr. J. Pohl-Pincus announces that by 

 an examination of the hair roots by polarized light, peculiar changes 

 may be observed whenever the patient suffers from physical irritation 

 or mental excitement. This statement is the result of investigations 

 which have now been going on for twenty-five years, and the later 

 observations in tho courso of the research have uniformly confirmed 

 those made earlier. 



The hair bulbs are divided into three groups, as follows : — Group 

 A : If, in healthy conditions of the body and mind, the hairs that 

 fall out daily are examined microscopically by polarized light, the 

 enlarged bulbous end of the root will show a white contour, and a 

 yellowish or brownish-red centre. Group B : In all irritable condi- 

 tions of moderate grade, all painful conditions of any organ, also in 

 emotional disturbances of moderate grade, without any apparent bodily 

 disease, the bulbous end of the hair root increases in length and breadth 

 (in proportion to the irritation), the central part appears under 

 polarized light of a violet, blue, or bluish-green colour, separated 

 from the white contour by bands of yellow and red. Group C : In 

 higher grades of bodily disease or mental disturbance, the bulb 

 becomes still larger, and the blueish centre changes to green, yellow, 

 or orange. A few hairs of the B and C types are found in normal 

 conditions, especially in those more advanced in life. Dr. Pincus 

 gives thirty-one cases showing the effects of painful disease, but more 

 especially of depressing emotions, upon the appearance of the hair 

 root. The conclusion to be derived from these researches is that bodily 

 disease or mental excitement causes circulatory disturbances, and in 

 consequence a change in the normal nutrition and pigmentation of the 

 hair. This is only in accordance with previous observations, and the 

 chief merit of the author's plan lies in his obtaining a means by 

 which very slight and temporary changes in tissue growth can be 

 detected and approximately measured. 



Feather-crystals of Uric Acid from a Caterpillar-t — Dr. S. 

 Lockwood prepares these crystals in the following way : — Have ready 

 say, six slides, absolutely clean. Puncture the caterpillar with the 



* Lancet, 1886, i. p. 848. 



t Journ. New York Micr. Soc, i. (1885) pp. 217-8. 



