The diagnosis of influenza in children is easy during an epidemic, but not in its absence. The following symptoms are distinctive: 1. The presence of influenza bacilli of Pfeiffer in the expectoration. 2. The simultaneous development of respiratory, digestive, and, at times, nervous phenomena. 3. Early and pro nounced prostration, incommensurate with the severity and duration of the attack. in addition to these differential points one must bear in mind the characteristic signs of all the other dis eases resembling influenza, such as pneumonia, meningitis, gastro-enteritis, typhoid fever, scarlatina, measles, con tinued hyperpyrexia, and rheumatism. H. B. Sheffield (N. Y. Med. Jour., June 30, 1900).
The occurrence of various forms of catarrhal fever, which arc often called grippe or influenza by physicians and laymen, is something altogether differ ent. Sporadic cases of coryza and bron chial catarrh should never be mistaken for influenza, although the symptoms of influenza may be imitated in an ex quisite manner. The celebrated Bonn professor's advice is that a complaint presenting catarrhal features should not be diagnosed as true influenza until the characteristic microbe has been found.
The most distinctive mark of typical severe influenza is its remarkably sud den onset, the only disease which re sembles it in this respect being Asiatic cholera.
Some of the symptoms are: Headache of a particularly racking type, frontal or orbital, often the precursor of de lirium; acute aches and pains in the back, not unlike those which are the forerunners of viola. The condition of the tongue is peculiar to the disease. According to Goodhart, it is generally tremulous, swollen, soft, and coated with a thick, creamy, dirty fur, accom panied usually by a particularly offen sive smell of the breath. The sweat, also, has an odor peculiar to this disease alone. Sometimes the coryzal symp toms are severe to a degree, and some times a dry and hard cough is an ac companiment. The temperature varies very considerably, occasionally running to a high point, but often rising to no appreciable extent. Rigors and drench ing sweats are a not uncommon feature in the course of the complaint. Good hart rightly lays especial stress upon the value in diagnosis of an extensive diffusion over the bases of the lungs of characteristic sharp, sticky riles. Edi torial (Med. Record, Jan. 19, 1901).
Influenza can be diagnosed with ease and certainty by observing the pecul iarity of appearance of the velum palati. It precedes the initial chill and fever by some days, and it persists when con valescence is apparently ended.
The phenomenon in question is seen upon the mucous membrane of the soft palate in the form of small, convex pro jections of a pearly whiteness or trans parency. Their size is that of a grain of
sand. In number they are either few and confined to certain parts of the velum or its processes or else abun dantly scattered over the whole of its anterior surface. The certain parts ex quisitely displaying them in their cir cumscribed form are: (1) the base of the uvula; (2) the median raphe; (3) the lateral borders of the same; (4) the anterior surface of the palato-glossal fold about the upper border of the ton sil. A spatula rubbed over them gives a hard, rough sensation.
They are not distinguishable in ob scure light, as in cloudy weather, nor discernible in any but a very bright arti ficial illumination, and are best seen in the sunlight, direct or diffused. They must not be confounded with minute drops of mucus or saliva often present. Sometimes they are entirely obscured by a tenacious secretion covering the sur face. The use of a handkerchief or the handle of a spoon to remove this gives the peculiar rough feel, and reveals the little projections on the mucous mem brane.
The color of the field to these bodies is flesh red in the otherwise normal in dividual; angry red from the consump tion of alcohol or use of smoking-to bacco; waxy white in the tuberculous and iu those subject to other wasting diseases. Sometimes punctate haemor rhages complicate the picture, and in a single instance the color of the little enlargements was bright red.
Their existence is devoid of any sub jective sensation. Louis Koplinski (Med. News, June I, 1901).
Etiology.—At the present time a large majority of medical writers and teachers assume that influenza is an infectious disease, caused by a specific bacillus. And they generally point to the bacillus dis covered in the pus-cells of the tracheal mucus by Pfeiffer in 1892, and in the blood by Canon the same year, as the essential cause of this disease. To the toxins developed by this micro-organism are also attributed the many and impor tant complications and sequelaa that ac company or follow a large proportion of the attacks. As early as the middle of the present century it was suggested by Dr. J. K. Mitchell, of Philadelphia, that the disease was caused by minute crypto gamic bodies in the air. In 1868 Dr. J. N. Salsbury, of Cleveland, claimed to have discovered a species of infusorium in the nasal discharges of a considerable number of cases which he regarded as the essential cause of the disease. The extraordinary rapidity of the spread of the disease over whole continents led nearly all of the older writers to attribute it to sudden and extreme changes in tem perature, moisture, and electric condi tions of the atmosphere, but no uniform ity of such changes has been found in different epidemics.