2o6 



NATURE 



[April 13, 191 1 



this theory the intraocular tension will var\- with the 

 relationship of secretion to excretion of lymph. It is 

 clearly a postulate of the theor>' that some alteration 

 in the volume of the Kl<^b« occurs under differing 

 internal pressures, though the necessary amount may 

 be so slight as almost to escape the ordinary crude 

 methods of experimental analysis. 



Dr. Henderson propounds a theor>' which is merely 

 the application of the Monro-Kellie doctrine of intra- 

 cranial pressure to the eye. This theory of intra- 

 cranial pressure has been proved substantially true 

 by the researches of Mr. Leonard Mill, and Dr. 

 Henderson, postulating the constancy of volume of 

 the eyeball under all pressures, physiological and 

 pathological, embarks upon a bold attempt to make all 

 the arguments fit in the case of the eye. He holds 

 that in the normal eye the total volume is constant, 

 the circulatory system is elastic, and that diffusion 

 takes place between the contained fluids and the return 

 (venous) circulation. Hence the intraocular pressure 

 is equal to the venous pressure of the elastic system. 

 In glaucoma the total volume is fixed, and there is an 

 absence of diffusion between the contained fluids and 

 the return circulation. Hence the fluid and incom- 

 pressible contents act as a rigid volume, converting 

 the clastic circulatory system into a rigid one. The 

 outflow pressure of a rigid system is always higher 

 than that of a similar elastic system of tubes. There- 

 fore the intraocular pressure is raised, as the lowest 

 circulatory pressure is that of a rigid, not an elastic 

 system. The starting point of the process in glau- 

 coma is held to be sclerosis of the cribriform or pec- 

 tinate ligament, whereby the diffusion of the aqueous 

 into Schlemm's canal is hindered. The explanation 

 of the success of iridectomy as a cure for the disease 

 is founded upon the fact that wounds of the healthy 

 iris stroma do not cicatrise in the ordinary manner of 

 connective tissues. The aqueous is thus brought into 

 more intimate contact with the iris veins, and is 

 enabled to drain away. 



It will be realised from this brief account that the 

 theory is revolutionary in its relation to certain 

 hitherto accepted facts. In some such instances 

 the author has audaciously thrown over the 

 facts. The most striking example of this procedure 

 concerns the anatomy of the ciliary circulation. No 

 one has previously questioned Leber's brilliant re- 

 searches on the circulation of the eye. Dr. Hender- 

 son, from an exhaustive examination of serial sections, 

 asserts that the circulus arteriosus iridis major is not 

 an artery but a vein. Adopting the teleological argu- 

 ment that there is no rhyme or reason for such an 

 abundant arterial supply to so insignificant a structure 

 as the iris, it is an easy step to transform arteries 

 into veins for the benefit of the theory. A\'e do not 

 consider that the examination of serial sections can 

 possibly prove the point conclusively, unless the blood- 

 vessels have been previously injected, as was done in 

 Leber's researches. It may be hoped that Dr. Hen- 

 derson or others will adopt this more conclusive test. 



Dr. Henderson's fundamental postulate, that of the 



constancy of volume of the eyeball under physiological 



and pathological pressures, cannot be accepted without 



reserve. Ihe walls of the eye, though rigid, cannot 



NO. 2163, VOL. 86] 



be regarded as rigid in the same sense as the w.iiis 

 of the cranium. There is experimental evld*-"'^'^^ 

 the contrary, notably that afforded by the r« 

 of Koster Gzn. Further, there is positive eviu' ncr .u 

 vasomotor changes in the intraocular blood-vessels, a 

 fact which militates against the theor>'. 



Moreover, if the intraocular pressure is purely .1 

 question of transmitted hydrostatic pressure in th*.- 

 sense of the term as used by Dr. Henderson, why dtK!> 

 the pressure fall slowly and gradually when the eye- 

 ball is excised? This and other questions will have 

 to be answered satisfactorily before the theory- can be 

 adopted. There is no doubt, however, that the author 

 has elaborated an important element of the problem. 

 His work should be read by all physiologists and 

 ophthalmologists, and cannot but prove to be stimulat- 

 ing to thought, and, it may be hoped, to further 

 experimental research. 



EXPERIMENTAL THERAPEUTICS. 

 Einfiihrung in die experimenielle Therapie. By Prof. 

 M. Jacoby. Pp. vii+180. (Berlin: J. Springer, 

 1910.) Price 5 marks. 



UNTIL the middle of last century therapeutics 

 was a purely clinical study, the physician 

 treating his patients on purely empirical grounds and 

 without any clearly conceived idea of how his 

 measures affected the course of the disease. About 

 fifty years ago the experimental study of the actitw) 

 of drugs was taken up by a number of investigators, 

 and the school of experimental pharmacology* suc- 

 ceeded to the ancient study of materia medica. The 

 benefits accruing to medicine from this school are 

 recognised by all who have followed the course of 

 therapeutics in the last half-century ; but its members 

 in some degree have stood aloof from the great move- 

 ment which, beginning with the discovery of patho- 

 genic organisms, has progressed to the discover}' of 

 their antidotes in the antitoxins, and to the treat- 

 ment of disease by these last. The workers 00 

 therapeutics who have approached the subject froo| 

 the bacteriological laboratory have accordingly- at^ 

 sumed a new and distinct title for it — experiment^ 

 therapeutics — and show a tendency to broaden its 

 borders to include such work as that which has cul- 

 minated in Ehrlich's discovery of the new anti- 

 syphilitic specific. Yet the methods followed fcjr 

 Ehrlich are exactly similar in essentials to those qf 

 Schmiedeberg or von Mering in their researches 

 hypnotics ; and the fact that the former was seekiojf 

 a remedy to act on the treponema in the tissues, aod 

 the others for a remedy for the over-excited nerve cell, 

 does not seem to justify their subjects being classed 

 under different headings. 



The book before us seeks to give a bird's-eye view 

 of the position of the subjects in therapeutics which 

 have recently been investigated experimentally. 

 Beginning with some examples of pharmacological 

 antagonism, the author leads us through the develop- 

 ment of the therapeutics of the internal secretion ■• 

 {Substitutioustlicrapie) to the experimental investiga- 

 tions on antiparisiticides ; under this he groups th< 

 treatment with vaccines, antitoxins, and Ehrlich'' 



