THE PROPAGATION OF PLAGUE WITHOUT THE AID OF INFECTED RATS.

322 Thomson Henderson’s writings gave an adequate expression of those opinions, but chiefly because it is only by enlisting the active interest and cooperation of physiologists that advance in our knowledge of the physiology and pathology of the intra-ocular pressure can be attained. I have so pro. found a respect for the views of those who are au fait with the latest researches in physiology that any criticism of Dr. Hill’s remarks which I venture to offer are put forward in the role of ad’Cooatu8 diaboli rather than that of confirmed antagonist. The statement which Dr. Hill controverts is founded upon the experimental work of Leber, Starling and Henderson, myself, and others. I have always been careful to state that the physical conditions of the formation of lymph " are consistent withor are " not inconsistent with"its production by a process of filtration, for I have never brought myself to believe that the living endothelial cells which form the walls of the capillaries and the retinal epithelial cells which cover the ciliary processes play a merely passive part in the production of the intra-ocular lymph. Such experimental work as I am familiar with appears to me to support the statement in the terms which I have used, and the deduction that there is a difference in pressure on the two sides of the capillary walls is thus far justified. The bald statement that "there is no evidence which demonstrates that there is a hydrostatic difference of pressure on either side of the capillary wall"" does not under these circumstances carry conviction. Dr. Hill apparently admits the physical process of filtration in the absorption of lymph, for he says that each pulsatile expansion in the arteries of the eye helps to drive a little of the aqueous into the efferent veins." With regard to Martin Fischer’s work, it appears to me to be as risky to apply such results obtained upon the excised eye directly to the living eye as it is to make deductions from a mechanical model. We know that an excised frog’s muscle will take up water from strong saline solutions against osmotic pressure ; it does not follow that the living muscle will behave in the same manner, and in fact it does not. The statement as to the action of sub-conjunctival injections in glaucoma has unfortunately been amply disproved. The suggestion, however, that the swelling of colloids is an important factor in glaucoma opens up a wide field for research, and if any remarks which I have made stimulate physiologists to direct their attention to the subject I shall be well repaid for any errors of which I may have I am, Sir, yours faithfully, been guilty. J. HERBERT PARSONS.

THE PROPAGATION OF PLAGUE WITHOUT THE AID OF INFECTED RATS. To the Editor of THE LANCET. SIR,-I have perused with considerable interest your leading article on this subject in THE LANCET of Dec. 16th, 1911. I

beg

to

forward, under separate

cover,

a

copy of my paper

Plague published in the American Journal of the Medical Sciences in September, 1909. I have tried therein to represent the views upon pneumonic plague which are held here, and which have been amply borne out by my clinical experience, now extending over 15 epidemics in this city. Whilst fully agreeing with Dr. R. Farrar as to direct infection in the propagation of pneumonic plague, there are other possible channels of infection that should not be overlooked, as you will find pointed out on p. 14 of my pamphlet. Should the apparent primary pneumonia be but a result of septicaemia,

on

then the intervention of the flea would be necessary, whether the tarabagan or the human flea, I am not prepared to say. The sequence of events would then stand thus : (1) Infected tarabagan ; (Z) infected flea of same ; (3) human infection, with rapid and early septicaemia followed by (4) pneumonia, apparently primary, but really secondary to blood infection. As regards the sputum infecting from secondary pneumonia in a case of bubonic plague, the chances of infection are infinitpsimal, though the probability could hardly be The complication is comparatively rare, and the denied. sputum not generally free or abundant. I have not come across any instances of infection in this way throughout my long connexion with the disease. I am, Sir, yours faithfully, N. H. M.D.

CHOKSY,

THE MORBID DIATHESES. To the Editor of THE LANCET. former house surgeon, Mr. MacIlwaine, credits me with little knowledge of the writings of my revered teacher, Dr. Moxon, and proceeds to contend against conclusions presumed to be in my Bradshaw lecture without apparently having read that address. My argument in refer. ence to the diatheses was that many diseases ’formerly dogmatically taught to be due to hereditary constitutional causes, such as tubercle, leprosy, malaria, rheumatism, had been proved by modern investigation to be due to tht in-roads of micro-organisms, or, to use the terms of our common teacher, had been removed from the intrinsic to the Extrinsic class. Nowhere do I deny that disease may not commence from defects in the organisation of any individual. But Mr. MacIlwaine’s illustrations are not all well chosen ;for nothing is more certain than that attacks of asthma may be caused by the pollen of certain plants and the odours of various animals, and "chronic lunacyis certainly not always dependent on a constitutional cause, for that form of chronic lunacy which is associated with general paralysis has been most clearly proved to be due to the degenerations caused by the ravages of the spirochseta pallida. I am, Sir, yours faithfully, R. CLEMENT LUCAS.

SIR,-My esteemed

METALLIC ELECTRIC COLLOIDS THEIR THERAPEUTICAL

AND

APPLICATIONS. of THE LANCET. with have read SIR,-I great interest M. Duhamel’a To the Editor

article on the use of metallic colloids in medicine in THE LANCET of Jan. 13tb. I was unaware that so much work had been done with this comparatively new therapeutic agent. M. Duhamel is undoubtedly an authority on this development of treatment in clinical medicine, but i think he is not justified in sweeping on one side all colloids of metals prcduced by chemical means as useless, and asserting that those produced by electrical means only are of value. The new metallic colloids of silver and mercury recently introduced by Mr. Henry Crookes, under the name of " collosols,"are made by an entirely novel chemical reaction and produce metallic colloids which are eminently stable and of great Brownian and bactericidal activity. The particles are of very small size and of perfect uniformity as seen under the ultra-microscope. It has also been found that when injected into the blood stream the particles do not block the capillaries. These collosols have been reported on by Professor Emil Hatschek as being "well made, free from reduced mercury and silver salt, and sufficiently stable towards electrolytes, heat, and the influence of organisms for all reasonable requirements." Mr. Crookes’s collosols are made of a standard strength, namely 500 parts of metal to 1,000,000 parts of liquid-i.e., 1 in 2C00. Laboratory experiments over a considerable period of time show that all bacteria experimented with are killed rapidly by one or the other of these collosols. The strength may be reduced to as little as 5 or 10 parts per 1,000,000, and in some cases as little as 1 part of silver per 1,000,000 has proved fatal to the bacteria in a few minutes. The bacteria experimented with were B. ooli conimunit, B. tuberculosis, daploeoaazcs gl"1IO’l’’l’haeae, various forms of stecphyloeaacus and streptococcus, and many others. The collosols are practically tasteless, of a reddish-brown colour, perfectly clear by transmitted light, and fluorescent by reflected light. They may be applied topically, hypodermically, intravenously, or by the mouth, and being non-toxic the dose hypodermically is unlimited, and experimental injections of 1 to 2 c.c. give little or no local or reactionary symptoms. It is necessary, of course, when giving hypodermically or intravenously that My own clinical proper and usual precautions be taken. experience with these chemical colloids during some months of recent practice entirely corroborates that of M. Duhamel with the electrical colloids, and I have treated the following cases with marked and surprising success. Topically: : Septic and follicular tonsillitis, Vincent’s angina, phlyctenular conjunctivitis, gonorrlceal conjunctivitis, spring catarrh. Impetigo contagiosus, acne of face and body, septio ulcers