VARICELLA is still described in most of the text books as a disease which is uniformly harmless, of characteristic appearance and which rarely needs any treatment.
In the past two decades, however, a number of interesting observa tions have been made which show that the ordinary conception of varicella is erroneous and that there may be complications which threaten life, great variations from the usual clinical picture and, what is of especial importance, it may often he confused with smallpox. The number of these observations is so great that more than mere mention of the most important of them is not possible in the allotted space.
It is impossible to state just how far back the history of varicella reaches. Hesse (1S29) cites a number of authors who thought they recognized varicella in the writings of the old Greek, Roman and Arabian physicians but they have not been able to present much evidence to support their views. However, in the writings of Vidus Vidius (1626) and sonic of his contemporaries (Ingrassius, Duncan Liddle) it is plain the clinical picture of varicella was well known and was differentiated from smallpox. Vidus named the disease Crystolli and mentions that the people call it Ram('lione, a name which is still used in Italy.
The history of varicella cannot be entered into. Suffice it to say that during the next two centuries many authors wrote upon the sub ject (see Hesse for citations) some claiming and others disclaiming its identity with smallpox.
Amongst those who recognized and described the disease may be mentioned Reberden (1767), Willan (1SOS), Heim (1S09) and Thom son (OS20, 21, 22). Hesse (1S29) has published the most complete monograph upon the subject.
The disease remained unknown by the great mass of practitioners and it was not until the introduction of inoculation and vaccination that the subject became one of general interest.
In the first decade of the nineteenth century, smallpox was noted in vaccinated persons and it also happened that varicella was frequently mistaken for smallpox. As the opponents of vaccination used this as an argument in favor of the uselessness of the procedure this little known disease, chicken-pox, was carefully studied and separated from smallpox.
The monographs of Willan (1SOS) and Heim (1809) showed that varicella was responsible for most of the so-called recurrences after vaccination.
In the following decades the idea that varicella was a separate disease gained ground and, in Germany at least, by the forties this was the common opinion of physicians.
About this time the influential Viennese dermatological school under Hebra declared dogmatically that varicella and variola were identical and it appears that physicians generally were converted to this opinion. The great smallpox epidemic of 1870-1873 again brought up the question of identity and a controversy was once more begun the vehemence and pertinacity of which is scarcely duplicated in medical history. As a result of this controversy most physicians have returned to the idea that varicella and smallpox are separate and distinct diseases.
Varicella originates only through infection, but concerning the nature of the contagion we know nothing and we can only surmise as to the method of transmission and as to its portal of entry into the body. It is certain that infection occurs easily when a child is brought into direct contact with one suffering from the disease, or when it remains in the same room for a short time. Infection through the air seems to play a considerable part in the transmission of the disease. The tenacity of the poison of chicken-pox is slight and is practically disregarded in practice and thus is just the opposite of smallpox in which the infec tious material may be carried great distances and live for almost in definite periods. Many physicians of great experience doubt if varicella is ever carried by a third person or by fomites.
The infectiousness begins with the appearance of the eruption (Cerf, 1901, and Apert, 1895) and disappears even before the last crusts have separated. The susceptibility to the disease is very general, espe cially during childhood. Daily experience teaches that when a child is taken ill in a family, closed institution, asylum or school the majority of the other children take the disease even if the child is at once isolated.