_Diagnosis of twin pregnancy._ Before concluding this chapter, we shall offer a few observations on the diagnosis of twins. A variety of symptoms have been enumerated as indicating the presence of two foetuses in utero, such as the great size of the abdomen, its flat square shape, the movements of a child at different parts of it, &c. The size of the abdomen can never be admitted as a diagnostic mark of twin pregnancy; first, because it equally indicates the presence of an unusual quantity of liquor amnii, or of a very large child; and secondly, because women pregnant with twins are not always remarkable for their size: the flatness, &c., of the abdomen is, we presume, a symptom based on the supposition that there is a foetus in each side of the uterus: this is very far from being correct, as it is well known that the children usually lie obliquely, the one being, perhaps, downwards and backwards, while the other is situated upwards and forwards. The sensation of the child's movements in different or opposite parts of the uterus is no proof whatever that there are twins, because it is constantly observed where there is but one child--a circumstance which is very easy of explanation. The stethoscope affords us the only certain diagnosis of twin pregnancy; and even here it is limited to the sounds of the foetal hearts; the increased extent and power of the uterine souffle, as remarked by Hohl, arising, as he supposed, from the large mass of the double placenta, is not a proof which can be depended upon. In cases of suspected twin pregnancy the auscultation must be conducted with the greatest possible care, and, generally speaking, a certain diagnosis can only be obtained by two observers ausculting the two hearts at one and the same moment; for, otherwise, the difference between their rhythm is frequently so small as to be inappreciable. The sounds are seldom or never heard at the same level, one being generally heard high up on one side, the other in a contrary direction. CHAPTER II. TREATMENT OF PREGNANCY. _Sympathetic affections of the stomach during pregnancy.--Morning sickness.--Constipation.--Flatulence.--Colicky pains.--Headach.-- Spasmodic cough.--Palpitation.--Toothach.--Diarrhoea.--Pruritus pudendi.--Salivation._