1881.] Dr. G. Thin. Absorption of Pigment by Bacteria. 503 



time to present a mechanical obstacle to their progress in growth from 

 one hair follicle to another.* 4 



IV. " On the Absorption of Pigment by Bacteria." By GrEORGE 

 Thin, M.D. Communicated by Professor Huxley, Sec. R.S. 

 Received February 19, 1881. 



Whilst occnpied with cultivation of ringworm hairs in vitreous 

 humonr at a temperature of 92 to 98° F., I had occasion to observe 

 in studying the hairs under the microscope, amongst the forms of 

 bacteria which were invariably found in these cultivations, certain 

 appearances that seem worthy of note. 



For the present, I shall limit my remarks to one of these ap- 

 pearances. 



It is known that certain fungi possess the property of taking up 

 colouring matter from the medium in which they grow ; and I have 

 had occasion to observe in the Trichophyton tonsurans that both in man 

 and in the horse the fungus may acquire a dark colour from absorbed 

 pigment. 



In the case of the horse, I have found the mycelial wall represented 

 by an apparently empty dark tube ; and I have found, at the same 

 time, spores blackened with a coating of pigment. 



I have found an analogous appearance in bacteria. 



The bacteria found in these cultivations are seen in the transition 

 forms of a spore or coccus, an elongating spore, rods, elongated rods, 

 sometimes of great length, long rods, with the first appearance of a 

 differentiation of the protoplasm into sporules, and finally as tubes 

 full of spores or cocci. 



These appearances have been now followed in several specific 

 organisms, and notably, and first of all, in the Bacillus anthracis. 

 They would seem to indicate the ordinary life-history of at least many 

 bacteria. 



I observed that frequently the preparations contained long bacteria 

 rods which had taken up pigment from the hair. This pigment was 

 often found at one end of a long rod, whilst towards the other end 

 the rod was free from it ; and in the part of the rod in which the 

 pigment was found the spore formation could, in several instances, be 



* As treatment which is destructive of bacteria would also arrest the develop- 

 ment of a fungus, it is desirable to add that in none of these cases, nor in previous 

 ones, was the author able to find the fungus described by Gruby, although a large 

 number of hairs were examined. The examinations thus made were so exhaustive 

 that he can only explain the alleged existence of a fungus in this disease by assum- 

 ing that the distinction between Alopecia areata and some of the forms of ringworm 

 has not been always kept in view. 



2 n 2 



