PHYSIOLOGY. 



645 



Dr. Caro Parascandolo, in experiments on dogs 

 and rabbits, has studied tlie lesions of the nervous 

 system that occur after burns of various degrees of 

 severity. He has found retraction of the gray 

 matter of the cord with deformed posterior cor- 

 nua and perinuclear and peripheric chromatolysis 

 in the cells; sometimes what he terms homogenei- 

 x.ation of the protoplasm ; sometimes granular de- 

 generation of chromatin with presence of chromatic 

 rods in the nucleus ; and sometimes total achrorna- 

 tylosis with destruction of the tissue network. . The 

 protoplasmic processes presented varicose atrophy 

 or lost their connection with the cell body and were 

 augmented ; and degeneration of the cord, affect- 

 ing the posterior cornua, was the rule. The author 

 concludes that as the result of burns ptomaines 

 make their appearance in the blood and muscles 

 and other organs of animals suffering from them, 

 and cause death by bringing about anatomical 

 changes in the nervous centers. The alterations 

 observable are similar to those met with in different 

 types of infection. It is particularly worthy of no- 

 tice that these ptomaines are capable by inoculation 

 of producing in the nerve centers the same lesions 

 as are observed in the case of burns. 



The salient points brought out in an investigation 

 by Prof. Louis Kahlenberg, of the University of 

 Wisconsin, of the action of solutions on the sense of 

 taste may be summarized as follow : In order that 

 a substance may affect the sense of taste, it must be 

 soluble in water, must be readily diffusible, and 

 must be capable of reacting chemically with the 

 protoplasm of the terminals of the nerves of taste. 

 The modern theories of solutions lead to the con- 

 clusion that the taste of a solution that conducts 

 electricity ought in general to be that of the ions 

 and the undissociated molecules that the solution 

 contains : sour taste is caused by hydrogen ions, 

 while hydroxyl ions produce an alkaline taste, which 

 in strong solutions is exceedingly disagreeable ; 

 chlorine ions have a salty taste, bromine ions one 

 that is similar, but slightly different in quality from 

 that of chlorine ions, while iodine ions have a salty 

 taste that is different in quality and less intense 

 than that of either chlorine or bromine ions. The 

 taste of N0 3 ions is slight, probably a trifle salty. 

 Only in strong solutions do they produce a sharp 

 burning sensation on the tip of the tongue. The 

 ions S0 4 and CH 3 COO have but very little taste, 

 the effect of the latter seeming to be a trifle sweet. 

 Tlie taste of sodium ions is slight, and is only im- 

 perfectly described as being a smooth effect on the 

 tongue, somewhat similar to that produced by a 

 very dilute solution of hydroxyl ions. Potassium 

 ions have a more pronounced taste, peculiar, bitter, 

 and rather disagreeable. Lithium ions have no 

 pronounced taste, having a similar effect, but less in 

 degree, with that of the sodium ions. Magnesium 

 ions are bitter, and calcium ions too, but with a 

 taste different in quality from that of magnesium 

 ions. Silver ions have a metallic taste and cause a 

 peculiar puckering sensation in the membranes of 

 the mouth cavity. The taste and effect of mercury 

 ions are somewhat similar to those of silver. The 

 intensity of the salty taste of the halogen ions de- 

 creases as the atomic weight increases. A relation 

 in the sense of the periodic law also appears to exist 

 between the taste and the atomic weights of the 

 cathions. Instances are found that point to the 

 conclusion that the greater the mobility of the ions 

 as measured by their speed under the influence of 

 the electric current, the more intense is the taste ; 

 but many exceptions point to the operation also of 

 other factors. The intensity of the taste of solu- 

 tions of substances containing amido-acid, alcoholic 

 hydroxyl. and aldehyde groups was investigated, 

 with results corresponding in general to what might 



be expected from the relative readiness w ith which 

 these substances permeate plant and animal mem- 

 branes. The alkaloids have in general a pronounced 

 bitter taste, as they permeate protoplasm rapidly and 

 exert a strong physiological action on the nerves ; 

 while colloid solutions are tasteless because the 

 substances they contain diffuse very slowly and are 

 chemically inert. 



In the examination of the color sensations of nearly 

 109 persons, Mr. G. J. Burch observed that by expos- 

 ing the eve to bright sunlight in the focus of a burning 

 glass behind a red screen a condition of temporary 

 red blindness is induced, during which scarlet ge- 

 raniums appear black and roses blue. Green blind- 

 ness a/id violet blindness may be produced by 

 similar means. The author has systematically 

 investigated the appearance of the spectrum during 

 the color blindness induced by exposure to intense 

 light from various parts of the spectrum, and finds 

 that the red from A to B. the green near E, the blue 

 halfway between P and G, and the violet at and 

 beyond H produce well-defined and characteristic 

 results, indicating that each of these colors corre- 

 sponds to a definite color sensation. In each case all 

 direct sensation of the color used for fatiguing the 

 eye is lost, but tlie observer is conscious of a positive 

 after-effect of the same color, by which the hue of 

 all other colors is modified. The temporary aboli- 

 tion of one color sensation is without effect on the 

 intensity of the remaining color sensations. Any 

 two, or any three, of the four color sensations red. 

 ereen, blue, and violet can be simultaneously or 

 successively exhausted. The observed facts are, in 

 the author's opinion, more in accordance with the 

 Young-Helmholtz theory than with that of Bering, 

 but they imply the existence of a fourth color 

 sensation, namely, blue. 



A number of cases of what may be called color 

 hearing, or the association of a sense of color witli 

 certain sounds, are described by Dr. W. S. Caiman. 

 who finds that they may fall into two groups. In the 

 first group a crude color sensation, often very beau- 

 tiful, is associated with certain sounds, as those of 

 the vowels severally, and of musical notes and in- 

 struments. The appearance is usually that of a 

 transparent film like a rainbow, in front of the ob- 

 server. In the second group color sensations occur 

 whenever letters or written words (symbols of 

 sound) are spoken or thought of, so that when a 

 word is uttered the subject visualizes the letters, 

 with each of which a distinctive tint appears. The 

 author is led from his studies of the subject to 

 regard the phenomenon as one of " associated sensa- 

 tions " analogous to the sensation of shivering 

 which we experience in one part or other of the 

 body at the sight or thought of an action, or when 

 having to endure certain disagreeable or squeaking 

 sounds. The tints excited are very definite and 

 characteristic, each for its own sound, and do not 

 vary as time goes on, while the colors are hardly 

 ever the same in two persons. 



Miscellaneous. The results of more than one 

 hundred cases are cited by MM. S. Arloing and Paul 

 Courmont as showing that the aggregation of the 

 tubercle bacilli when the blood serum is introduced 

 into a culture may furnish, very rapidly, an im- 

 portant element of" information in the early diag- 

 nosis of true tuberculosis. In two cases, however, 

 the test failed, though tuberculosis was undoubted 

 and in an advanced stage. The fact that positive 

 results were almost always obtained when tlie 

 tuberculosis lesions were in an early stage is taken 

 as showing that the serum reaction is the more 

 valuable. Feeble aggregation was induced in some 

 cases where tuberculosis was not found by the 

 ordinary clinical methods, and the inference is 

 drawn that latent tuberculosis may be consistent 





