REVIEW — TROPICAL MEDICINE, ETC. 163 



Eogers' deals with the blood changes in plague, and quotes Acoyama, who found a very Plague— 



marked leucocytosis present, occasionally exceeding 100,000, most commonly due to excess 

 of polynuclears, but sometimes showing a lymphocytosis instead. Tliere is an occasional 

 absence of leucocytosis, however, in some very severe or very mild cases. The differential 

 leucocyte count was found often to present a peculiarity which may be of diagnostic value. 

 Thus : — 



In the leucocytosis of pneumonia and ordinary septic conditions, there is a marked 

 relative increase of the polynuclears, mainly at the expense of the lymphocytes, so that the 

 former number somewhere about 90 per cent., and the lymphocytes only about 10 per cent. 

 In the leucocytosis of plague, on the other hand, the percentage of lymphocytes may not be 

 reduced and may even be actually somewhat high, over 20 per cent, being not infrequently 

 met with, so that the total number of lymphocytes is markedly increased. Unfortunately, 

 this lymphocytosis was only met with in half the cases examined during the first three days 

 of the disease, so that, although its presence is an important aid to the diagnosis, yet its 

 absence in no way excludes the presence of plague. The large mononuclears are not 

 increased, but tend to be low, a point which has served to differentiate plague from malaria. 



As regards bacteriological examinations in plague, Eogers says : — 



Firstly, a careful search should be made for any primary vesicle on the skin drained by the affected lymphatics 

 in bubonic cases, for these are most frequently met with in the mildest, and therefore the most difficult, 

 cases to distinguish, and they are by no means rare in my experience. If found, the fluid contents should be 

 withdrawn with a sterile syringe after carefully cleansing the skin, and cultures and slides for microscopical 

 examination made. 



Secondly, if no primary vesicles are present, but there is enlargement of a group of lymphatic glands, the 

 latter should be punctured in a similar way, in order to ascertain if plague bacilli are present in them, or only 

 staphylococci, as in cases of " climatic bubo." It must, however, be borne in mind that in the suppurative stage 

 of plague, buboes, the specific bacilli, may be absent, and only staphylococci found. Before the suppurative stages, 

 very numerous short bi-polar staining bacilli of plague, will be obtained in this way. These are quite characteristic 

 of the disease, and will enable prompt action to be taken without waiting for the confirmation which will be 

 afforded by the cultivation of the organisms. 



Thirdly, in the absence of buboes, either the septicaemic or pneumonic forms of plague may be present. It 

 the former is suspected a small sjrringe-full of blood should be taken from a vein in the arm and cultures made 

 both on agar and in broth, and films stained and examined microscopically. In the latter stages of the disease, 

 which may be reached as early as the second or third day, the characteristic bi-polar staining bacilli may be present 

 in the circulation in sufficient numbers to allow of their being detected by a microscopical examination and 

 readily isolated by culture. In making cultures from the blood, from 1 c.c. to 2 c.c. should be added to from 50 c.c. 

 to 100 c.c. of broth in a flask to which a few drops of oil may be added in order to obtain the characteristic 

 stalaotitic growth of the plague bacillus. E. D. W. Qreig, I. M.S., has recently recorded th.at by this means he 

 cultivated the organism from the blood of 59-8 per cent, of all kinds of plague cases examined soon after admission 

 during the first three days of the disease, the mortality of the positive cases being 97 per cent., while that of the 

 negative was only 43 per cent., so that this method also furnishes evidence of prognostic value. 



In pneumonic cases the sputum will show innumerable plague bacilli, often in almost pure culture, and will 

 also allow of the organism being isolated in plates, so a microscopical examination should never be omitted in any 

 case of pneumonia which may possibly be due to plague. 



Much work has been done at the agglutination test in the serum diagnosis of pLague, but it has not been found 

 to give satisfactory results, and is altogether inferior to the methods above described. 



Hossack- has a useful paper dealing chiefly with rats and fleas in India. Phenyl is 

 recommended as a pulicide, and a table given comparing it with other disinfectants. 

 References to this subject will be found under " Disinfection" {pdge 44). Eamachandrier,^ 

 in a very practical kind of paper on prophylaxis, has some quotable remarks on rat 

 destruction. One notes that traps must be of superior quality and must be kept scrupulously 

 clean and free of rat smell. The least smell of the previous day's rats in the cages prevents 

 other fresh rats coming in, hence the traps must be fully immersed in hot water every day 

 and kept in the sun during the whole day. Fresh pieces of mutton or of dried fish constitute 

 tlie most tempting forms of bait. The virtues of tire cat as a rat-killer are extolled in this 

 paper, which concludes with very sound advice to natives on personal precautions, and is 

 altogether well worth careful perusal. 



Buchanan'' was, I think, the first to advocate the keeping of cats as plague preventers, 

 and he concludes a short but interesting paper on the subject as follows : — 



The value of a plague prevention measure depends on four things : fii-st, whether it is effective ; second, whether 

 it strikes at the root of the disease ; third, whether it is available ; and fourth, whether it is acceptable to the people. 



' Rogers, L. (London, 1908), " Fevers in the Tropics." 



- Hossack, W. C. (March loth, 1907), " Bats and Plague." Journnl of Tropical Medicine and Hygiene, Vol. X. 

 ' Ramachandrier, P. S. (August, 1907), " The Prophylaxis of Plague." Indian iTedical Gazette, Vol. XLII. 

 ■• Buchanan, .\. (October, 1907), "Cats as Plague Preventers." Indinn Afeilii^n! Onzette, Vol, XLII. 



continued 



