654 



PHYSIOLOGY. 



of prcteidlike substances have been described by 

 Dr. John W. Pickering. From them it appears 

 that if certain derivatives of proteids and other sub- 

 stances of allied chemical constitution are heated 

 together in sealed tubes with an excess of either 

 phosphorus pentaehloride or .pentoxide a series of 

 colloidal substances are formed which, when freed 

 from the contaminating phosphoric acid and dis- 

 solved in concentrated ammonia, give opalescent 

 solutions that, on evaporation down in a vacuum, 

 yield substances closely resembling in physical, 

 chemical, and physiological properties certain pro- 

 teids. These colloidal substances, although they 

 differ from one another in minor details, are usu- 

 ally distinguished by the following characteristics: 

 they are soluble in warm water, forming opalescent 

 Itevorotatpry solutions ; the resulting solutions yield 

 the principal color reactions hitherto deemed diag- 

 nostic of proteids; in the absence of salts, solutions 

 of these colloids do not coagulate on healing, but in 

 the presence of a trace of a neutral salt they coagu- 

 late at temperatures very similar to proteid solu- 

 tions: fractional heat coagulation shows that the 

 colloidal solutions are mixtures of different sub- 

 stances ; the different constituents of the colloidal 

 solution exhibit different physiological actions: in 

 the presence of an excess of neutral salts, or of salts 

 of the heavy metal, the colloidal solutions behave 

 in a manner similar to proteid solutions ; when in- 

 troduced into the circulation of pigmented rabbits, 

 dogs, and cats certain of these substances produce 

 intravascular coagulation of the blood in a manner 

 similar to a nucleo-proteid. They also hasten the 

 coagulability of the blood withdrawn from the ca- 

 rotid, and will, when slowly injected intravenously 

 in minute quantities into dogs, produce a retarda- 

 tion of the coagulability of the intravascular blood, 

 e.g., a "negative phase." Apparently these col- 

 loidal substances are, owing to both their physical 

 and chemical properties and their physiological be- 

 havior, the synthesized bodies nearest to proteids at 

 present known. 



Dr. A. B. Macallum has found that the greater 

 part, and sometimes the whole of the assimilated 

 iron in the cells of the higher forms of animal life is 

 held in the nucleus, in the chromatin of which it 

 is chiefly found ; and the same is true of the nuclei 

 of all the higher vegetable organisms; it is rarely 

 found in the cytoplasm of the cells. An important 

 section of the author's paper is given to the occur- 

 rence of assimilated iron in special forms of life, such 

 as in protozoa, fungf, bacteria, and the Cyanoplnjctp. 

 Chlorophyll yielded no evidence that it contains 

 iron, and it is mentioned incidentally that species 

 of Monotropa remain colorless when fixed in solu- 

 tions of corrosive sublimate. 



Concerning the bacteriology of oysters, Profs. 

 Herdman and Boyce said, in the British Associa- 

 tion, that it had been shown that sea water is very 

 deadly to the typhoid bacillus, so that an infected 

 oyster would probably soon be free from infection. 

 It has been found, as an experimental result, that 

 artificially infected oysters soon get rid of their ty- 

 phoid bacilli. Moreover, there is normally in the 

 oyster a bacillus resembling that of enteric fever, 

 by which an inexperienced investigator might easily 

 be misled. IH the discussion Dr. Kohn showed 

 that the pigment causing the green color in the 

 gills of certain oysters is not due to iron or copper, 

 as has been supposed, since the body contains even 

 larger quantities and is not colored. Dr. Griin- 

 baum spoke on the action of human serum on ty- 

 phoid bacilli as tending to show the normal pres- 

 ence of certain protective substances, varying in 

 quantity in different individuals, more particularly 

 in mother and child. 



The nature and causes of immunity to disease, 



natural and acquired, are discussed by Dr. W. B. 

 Ransom in the light 'of a large number of facts 

 cited and reviewed. The author concludes that im- 

 munity can not be due to " exhaustion of the soil " 

 or the using up by the bacteria of certain constitu- 

 ents of the animal body necessary for their food ; 

 for it may be produced without bacteria entering 

 the body at all, and it has been shown that the 

 fluids of animals naturally or artificially immune 

 may form good culture media. The last fact also 

 disproves the theory that it is due to the retention 

 in the body of bacterial products harmful to them- 

 selves. Dr. Ransom's conclusion is that immunity, 

 whether caused by gradually accustoming the body 

 to the action of a microbe or its toxine, or by inject- 

 ing into another the serum of an animal thus pro- 

 tected, is in each case due to a vital reaction of the 

 cells of the body, and that in each case the injected 

 substance stimulates to that reaction. Such reac- 

 tion is shared in by all the cells of the organism. 

 They all become less sensitive to the microbic toxine. 

 while the special defensive mechanisms are stimu- 

 lated to the more active exercise of their special 

 functions. Immunity then depends on the action 

 of living cells. In resisting the invasion of living 

 bacteria, there is a defensive mechanism in the 

 army of phagocytes, but this alone can not suffice. 

 Changes in the fluids of the body, rendering them 

 a less suitable pabulum, or even actually bacteri- 

 cidal, are produced by changes in all the cells by 

 virtue of which they become comparatively insen- 

 sitive, though they do not, so far as we know, secrete 

 a chemical antidote. 



In comparative experiments made by Prof. Char- 

 teris and Dr. MacLennan regarding the lethal dose 

 of hydrochlorate of eucaine and hydrochlorate of 

 cocaine injected into guinea pigs, it was found that 

 the toxic dose of the eucaine was O09 gramme, and 

 that of cocaine 0'068 gramme, per kilogramme body 

 weight. The mode of death from the two substances 

 varied. With the cocaine salt there were more rota- 

 tory movements of the head, more salivation, more 

 opisthotones, and more respirations than with the 

 eucaine salt. It was also noticed that the physio- 

 logical action produced by a given dose of eucaine 

 did not follow nearly so rapidly as that which en- 

 sued with a similar dose of cocaine under identical 

 conditions. Hence it was concluded that the action 

 of eucaine was slower in onset and less in intensity. 



Toxines are defined by M. Armand Gauthier as 

 poisons secreted by microbes or formed by the ani- 

 mal economy which, if introduced into our organs 

 or not completely eliminated, bring on a patholog- 

 ical state and involve profound and often permanent 

 modifications of the nutrition and of the vitality of 

 the cellules. Those toxines are of 3 kinds : the 

 ptomaines, definite alkaloidal poisons formed by the 

 microbes; leucomaines, basic substances, definite, 

 like the ptomaines, but formed in our organs in the 

 regular course of life : and tu.rines, properly so 

 called, poisons either albuminoid or of an indeter- 

 minate chemical nature, playing in general the part 

 of ferments of surprising activity. They are se- 

 creted by pathogenous microbes as well as by veno- 

 mous animals and certain plants. They form an 

 essentially injurious portion of venom and virus. 

 Along with the microbial toxines the author in his 

 work on " Animal and Microbial Toxines" describes 

 the soluble ferments, animal and vegetable, and 

 the specific glandular secretions as well as those 

 curious antitoxines which the living organism pro- 

 duces when it reacts and defends itself against the 

 attacks of those dangerous agents. There are other 

 antitoxines now used in seropathy. 



The observations of Prof. II. B. Bowditch on 

 Boston school children and those of Dr. Porter on 

 St. Louis children go to show that the relation be- 



