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TYPING THE TYPHOID BACILLUS
1476 would be a useful piece of evidence. In reply Dr. Shapiro said that this was being investigated. SEMEN ANALYSES IN FERTILE MEN
has become a sine qua an infertile marriage. In order, however, that departures from fertility may be recognised, a standard of normality is essential. This is not easily established, since men whose fertility has been proved by their wives having become pregnant do not submit their semen to analysis. For this reason the semen analyses of 200 fertile men made by Hotchkiss, Brunner, and Grenley1 are of great interest. The wives of these men were all in the first half of gestation. The fertilising value of semen seemed to depend on a combination of four basic factors : its volume ; the number of spermatozoa present; their grade of motility ; and the percentage of abnormal forms. In this series the average volume of semen was 3 c.cm. When a condom was used for its collection the volume was reduced, and the motility of the spermatozoa was at the same time impaired. In 25 of the cases the spermatozoa count was below the sixty million level. No constant relationship was found to exist between the amount of ejaculate and the spermatozoa count, but as a rule larger ejaculates gave higher counts. The authors consider that a determination of the pH of the semen is only necessary when spermatozoa motility is reduced, and that estimation of the sugar content of the semen is of no apparent value. This paper is important for all who are interested in the question of male fertility and infertility. Rarely, if ever, has so good an opportunity been provided for studying the constitution of normal semen of proven fertility. THE
non
analysis of the semen investigation of
in the
TYPING THE TYPHOID BACILLUS
Two years ago Craigie and Brandon2 of Toronto described a bacteriophage which was specific for the Vi form of Bacillus typhosus. In a follow-up of this work Craigie and Yen 3 elicited four serological types of Vi-specific phage, one of which, Phage 2, seemed to attack different strains of typhoid bacillus with varying intensity. This phenomenon was shown to depend on the fact that Phage 2, when propagated on a certain strain, develops a high lytic activity for that strain but not for other unrelated strains ; extension of this observation resulted in the differentiation of a large collection of strains of B. typhosus into a limited number of groups, tentatively labelled Types A to J. A fairly simple technique has been devised for quickly assigning any strain to its approper cent. of 592 typable cultures have been allocated to one or other of six main types. Of over 700 cultures, many of them already frequently subcultured, only about a tenth could not be typed because they were " imperfect Vi forms," while a smaller proportion did not contain any Vi antigen. It now became essential to test the stability of these types and this was done in various ways-by picking a dozen or more colonies from one culture, by testing the same culture at varying intervals of time, by comparing cultures of the same strain maintained at different centres, and, lastly, by correlating the types with epidemiological data. The in-vitro tests failed to show any lack of typestability, while from several cases and carriers one
priate type, and,
as a
result, 98.6
1 Amer. J. med. Sci. September, 1938, p. 362. 2 J. Path. Bact. 1936, 43, 233. Canad. publ. Hlth J. September and October, 1938, pp. 448 and 484. 3
and one type only was repeatedly recovered. A detailed analysis of the sources of the strains under examination showed an almost complete agreement between the epidemiological findings and the type of bacillus isolated from the individuals involved. The few discrepancies could be readily explained. The significance of these observations is obvious. The isolation of the same type of B. typh08u8 from a carrier and a series of patients whom the carrier is suspected of having infected would add strong bacteriological support to the epidemiological evidence. The present investigation has, in fact, already given bacteriological backing to the evidence as to source of infection not only in numerous Canadian outbreaks but also in the recent Croydon and Bournemouth epidemics, by proving the identity of the carrier strain with strains derived from infected patients. No doubt this work will lead to a re-examination of the Vi antigen to see whether types of B. typhosus can be differentiated serologically. In the meantime the technique described by Craigie and Yen is one which, given the phage preparations, could be readily adopted in any up-to-date laboratory ; the fallacies are few and the typing of freshly isolated strains of typhoid bacillus is likely to be both straightforward and speedy.
type
ANÆSTHETICS FOR ANIMALS
FEW
people are aware of the amount of study that given to-day to anaesthesia in veterinary surgery or of the wide extent and efficiency with which the results are being applied. In a paper read to the 13th International Veterinary Congress, J. G. Wright1 reveals some of the difficulties confronting the ansesis
thetist who has to deal with animals as different as a horse and a cat. Compared with these, problems of meeting the requirements of the anaemic young house-
keeper and the hard-drinking hunting squire seem simple. Moreover, animals of the same species show almost as great individual differences in reaction to narcotic drugs as do human beings. The barbiturates have proved even more useful in animal surgery than in man, though in the horse the huge doses necessary prohibit their use on grounds of cost. For this animal about five grammes of chloral hydrate so that the animal can be quietly cast, followed by open chloroform, appears to be the method of choice. For the dog Wright considers Nembutal the best anaesthetic for all extensive surgical procedures and recommends it also for the many minor operations which hitherto have been usually performed under morphine. It is interesting that animals, like human beings, are subject to excitement during recovery from barbiturate anaesthesia. ANGIOCARDIOGRAPHY
IN the first issue of
a new
Havana medical
journal
Castellanos, Pereiras, and Garcia2 describe their method of radiography of the heart and great vessels after the intravenous injection of opaque fluid. Angiocardiography is mainly applicable to congenital malformations in children, and can be used after death where a full post-mortem examination is refused. The best results are obtained in patients under twelve years, because their skeleton is not
yet fully calcified and their blood volume is comparatively small, so that the opaque fluid is not too rapidly diluted. The patient is strapped on the X ray couch to prevent movement during screening, and a 1 J. comp. Path. September, 1938, p. 166. Castellanos, A., Pereiras, R., and Garcia, A., Rev. Cienc. méd., Havana, July, 1938, p. 1. 2
has become a sine qua an infertile marriage. In order, however, that departures from fertility may be recognised, a standard of normality is essential. This is not easily established, since men whose fertility has been proved by their wives having become pregnant do not submit their semen to analysis. For this reason the semen analyses of 200 fertile men made by Hotchkiss, Brunner, and Grenley1 are of great interest. The wives of these men were all in the first half of gestation. The fertilising value of semen seemed to depend on a combination of four basic factors : its volume ; the number of spermatozoa present; their grade of motility ; and the percentage of abnormal forms. In this series the average volume of semen was 3 c.cm. When a condom was used for its collection the volume was reduced, and the motility of the spermatozoa was at the same time impaired. In 25 of the cases the spermatozoa count was below the sixty million level. No constant relationship was found to exist between the amount of ejaculate and the spermatozoa count, but as a rule larger ejaculates gave higher counts. The authors consider that a determination of the pH of the semen is only necessary when spermatozoa motility is reduced, and that estimation of the sugar content of the semen is of no apparent value. This paper is important for all who are interested in the question of male fertility and infertility. Rarely, if ever, has so good an opportunity been provided for studying the constitution of normal semen of proven fertility. THE
non
analysis of the semen investigation of
in the
TYPING THE TYPHOID BACILLUS
Two years ago Craigie and Brandon2 of Toronto described a bacteriophage which was specific for the Vi form of Bacillus typhosus. In a follow-up of this work Craigie and Yen 3 elicited four serological types of Vi-specific phage, one of which, Phage 2, seemed to attack different strains of typhoid bacillus with varying intensity. This phenomenon was shown to depend on the fact that Phage 2, when propagated on a certain strain, develops a high lytic activity for that strain but not for other unrelated strains ; extension of this observation resulted in the differentiation of a large collection of strains of B. typhosus into a limited number of groups, tentatively labelled Types A to J. A fairly simple technique has been devised for quickly assigning any strain to its approper cent. of 592 typable cultures have been allocated to one or other of six main types. Of over 700 cultures, many of them already frequently subcultured, only about a tenth could not be typed because they were " imperfect Vi forms," while a smaller proportion did not contain any Vi antigen. It now became essential to test the stability of these types and this was done in various ways-by picking a dozen or more colonies from one culture, by testing the same culture at varying intervals of time, by comparing cultures of the same strain maintained at different centres, and, lastly, by correlating the types with epidemiological data. The in-vitro tests failed to show any lack of typestability, while from several cases and carriers one
priate type, and,
as a
result, 98.6
1 Amer. J. med. Sci. September, 1938, p. 362. 2 J. Path. Bact. 1936, 43, 233. Canad. publ. Hlth J. September and October, 1938, pp. 448 and 484. 3
and one type only was repeatedly recovered. A detailed analysis of the sources of the strains under examination showed an almost complete agreement between the epidemiological findings and the type of bacillus isolated from the individuals involved. The few discrepancies could be readily explained. The significance of these observations is obvious. The isolation of the same type of B. typh08u8 from a carrier and a series of patients whom the carrier is suspected of having infected would add strong bacteriological support to the epidemiological evidence. The present investigation has, in fact, already given bacteriological backing to the evidence as to source of infection not only in numerous Canadian outbreaks but also in the recent Croydon and Bournemouth epidemics, by proving the identity of the carrier strain with strains derived from infected patients. No doubt this work will lead to a re-examination of the Vi antigen to see whether types of B. typhosus can be differentiated serologically. In the meantime the technique described by Craigie and Yen is one which, given the phage preparations, could be readily adopted in any up-to-date laboratory ; the fallacies are few and the typing of freshly isolated strains of typhoid bacillus is likely to be both straightforward and speedy.
type
ANÆSTHETICS FOR ANIMALS
FEW
people are aware of the amount of study that given to-day to anaesthesia in veterinary surgery or of the wide extent and efficiency with which the results are being applied. In a paper read to the 13th International Veterinary Congress, J. G. Wright1 reveals some of the difficulties confronting the ansesis
thetist who has to deal with animals as different as a horse and a cat. Compared with these, problems of meeting the requirements of the anaemic young house-
keeper and the hard-drinking hunting squire seem simple. Moreover, animals of the same species show almost as great individual differences in reaction to narcotic drugs as do human beings. The barbiturates have proved even more useful in animal surgery than in man, though in the horse the huge doses necessary prohibit their use on grounds of cost. For this animal about five grammes of chloral hydrate so that the animal can be quietly cast, followed by open chloroform, appears to be the method of choice. For the dog Wright considers Nembutal the best anaesthetic for all extensive surgical procedures and recommends it also for the many minor operations which hitherto have been usually performed under morphine. It is interesting that animals, like human beings, are subject to excitement during recovery from barbiturate anaesthesia. ANGIOCARDIOGRAPHY
IN the first issue of
a new
Havana medical
journal
Castellanos, Pereiras, and Garcia2 describe their method of radiography of the heart and great vessels after the intravenous injection of opaque fluid. Angiocardiography is mainly applicable to congenital malformations in children, and can be used after death where a full post-mortem examination is refused. The best results are obtained in patients under twelve years, because their skeleton is not
yet fully calcified and their blood volume is comparatively small, so that the opaque fluid is not too rapidly diluted. The patient is strapped on the X ray couch to prevent movement during screening, and a 1 J. comp. Path. September, 1938, p. 166. Castellanos, A., Pereiras, R., and Garcia, A., Rev. Cienc. méd., Havana, July, 1938, p. 1. 2