May 29, 1914] 



SCIENCE 



795 



the incrimination of tlie biting stable fly, Stomoxys 

 calcitrans, alone. These cliaracteristics and the 

 species studied are given below. 



The distribution of pellagra and its occurrence 

 in persons seemingly not exposed to attack by lice, 

 possibly, also, the sex incidence, are not satisfac- 

 torily explained by their incrimination. 



Bed bugs, though abundant, fail to account for 

 the sex incidence of pellagra, while the habits and 

 scarcity of horse-flies exclude them. 



The prevalent mosquitoes, Culex quinquefaciatus 

 {■=fatigans) are nocturnal in habit and the day- 

 biting Aedes calopits ia of irregular occurrence in 

 the region. 



The human flea, Fulex irritant, is rare or want- 

 ing in the county. Fleas of animals cause little an- 

 noyance and they do not explain the sex incidence. 



Simulium species do not associate with man and 

 pellagra sufferers are usually rarely exposed to 

 their attack. They are negligible as a pest of man 

 in the region. Pellagra occurs, also, in regions 

 from which they are absent. 



Sand flies (Chironomidse), if present, are not a 

 pest in the region. 



The stable fly is a practically cosmopolitan and 

 abundant species; it associates with man, invades 

 his dwellings and attacks him freely; it bites by 

 day and its longevity is considerable. Human 

 blood has been determined in the stomachs of an 

 important percentage of individuals and human 

 blood may be drawn without pain, in many in- 

 stances. 



If the cause of pellagra is an intestinal bac- 

 terium, the house fly may very probably be a ve- 

 hicle for its diffusion. 



The house-infesting roaches, in this event, may 

 also play a minor part. 



Discussion of Pellagra — Mental Disturbances: E. 



Bates Block, M.D. 



There is no one type of mental disturbance char- 

 acteristic of pellagra. Insanity is usually a late 

 manifestation of the disease and when it occurs it 

 usually means that the end is near. As a terminal 

 event it usually assumes the type of the infective 

 exhaustive psychoses, with clouding of the con- 

 sciousness, confusion, hallucinations and changing 

 delusions, with marked restlessness and apprehen- 

 siveness. 



When the insanity occurs earlier in the disease 

 before the exhaustion becomes marked, it is usually 

 characterized by great depression with delusions 

 which are depressive or persecutory in character. 

 This is associated with marked apathy or restless- 



ness and general nervousness and insomnia, and 

 sometimes with excruciating headaches. Mental 

 confusion is quite common; apprehensiveness is 

 often a marked feature of the disease. Suicidal 

 attempts are quite common, but in only one of the 

 cases which I have seen has there been any viol- 

 ence towards others. 



Sometimes the insanity precedes the physical 

 signs of pellagra as a part of the disease. While 

 insanity does not confer immunity to pellagra and 

 the sequence may have been accidental, I have seen 

 several cases which have developed insanity sud- 

 denly and were so shortly followed by symptoms of 

 acute pellagra that I believed them to be a part 

 of the same disease. One of these was apparently 

 typically psychasthenia, another melancholia, while 

 a third was apparently manic depressive insanity, 

 but all were quickly followed by the typical signs 

 of pellagra. The prognosis in these cases is much 

 more favorable than in the eases in which the in- 

 sanity developed as a late manifestation of the 

 disease. Occasionally the apathy is so great as to 

 suggest dementia prEeeox and the cases of this type 

 that I have seen have run a very chronic and pro- 

 tracted course. 



The development of insanity is not necessarily 

 of fatal significance. In one of my cases the pa- 

 tient has remained perfectly well now for eight 

 years and in another for five years, without any 

 recurrence either of mental or physical symptoms. 



The prognosis of pellagra was discussed by Dr. 

 George M. Niles, of Atlanta, Ga., as follows: 



My experience in the treatment of over six hun- 

 dred cases of this malady has made me somewhat 

 optimistic, and I feel that the attitude of extreme 

 pessimism assumed by some observers is unjusti- 

 fied. 



Pellagra, like some other diseases, seems more 

 virulent when implanted on virgin soil. We note 

 that in the Old World, where it has been rife for 

 nearly two centuries, the mortality is not near so 

 great. In this country it is in many respects a 

 new enemy, and its prospective victims have not 

 been able to establish, as it were, any form of 

 immunity against its ravages. 



In my professional intercourses with pellagrins 

 and their inquiring friends I have adopted a 

 classification as to the conditions in which a favor- 

 able outcome may be anticipated, or the reverse. 

 There are four classes in whom I am extremely 

 chary in holding out a favorable prognosis: First, 

 pellagrins over fifty or fifty-five years of age. 

 The pathologic changes of this disease closely sim- 

 ulate those of senility, and when to the changes 



