54 



off by drying the acid at 105 to 110 C. Bertrand 89 says that 

 the lac must be handled with the greatest precaution because the 

 least traces in the state of vapor produce on the face, hands and 

 arms an intense rubrefaction accompanied by intense itching, and 

 adds that these malicious properties make the study of lac very 

 unpleasant, and he was obliged to interrupt his studies on account 

 of individual sensibilities. 



With these statements before me it was not without mis- 

 givings that I undertook the study of lac, and these were not 

 allayed by my first experience. The first sample received was 

 in a glass can with metal top which had become sealed by the 

 lac, and was difficult to remove, but when finally started was 

 accompanied by a slight sound of escaping gas. In about thirty- 

 six hours an inflamed spot about 2 cm. by 5 cm. appeared on my 

 wrist ; it itched intensely for about a week and then disappeared. 

 Laboring under the supposition that I was dealing with a volatile 

 poison, I was extremely cautious not to come in contact with the 

 vapors in any form, but supposed that I was practically safe after 

 the alcohol had been distilled and the residue had been heated 

 for some time. While shaking out an ether solution of the 

 alcoholic residue with sodium carbonate solution, it was difficult 

 to keep the hands entirely free from the solution and no especial 

 pains were taken to remove it except to carefully wash with soap 

 and water. However, after working some time with it my face 

 began to swell and continued until my eyes were nearly closed. 

 It extended over hands, arms and limbs to the knees ; the desire 

 to scratch was very great so that it was almost impossible to 

 sleep. This was also true of the face and ears to some extent, 

 but here the sensation was more that of burning. After about a 

 week the face became normal and I was able to resume my work 

 but the limbs continued to itch and remained covered with a fine 

 rash. After several weeks I became convinced that the underwear 

 had absorbed some of the poison and though frequently washed 

 still retained it. Soft gauze underwear was then worn next the 

 skin, when the flesh soon became normal. 



Various remedies were tried, such as, ointment of zinc 

 oxide ; a mixture of oxide of zinc, bismuth subnitrate, starch and 

 solution lead subacetate, tincture of iodine with glycerin ; solu- 

 tion of potassium permanganate ; solution of oxalic acid. None 



Annales de Chimie et de Physique, Series XII, 1897. 



